Enable size_t to int truncation warnings in PPAPI

Also removed a few extra "-Wpedantic" warnings in ppapi_cpp. I don't see a good justification why this should be different than the rest of the project.

Fix GN error in media.

NOPRESUBMIT=true

Review URL: https://codereview.chromium.org/915403003

Cr-Commit-Position: refs/heads/master@{#316289}

59 files changed, 192 insertions, 201 deletions

diff --git a/media/BUILD.gn b/media/BUILD.gn
index 9773484..d9e2399 100644
--- a/media/BUILD.gn
+++ b/media/BUILD.gn
@@ -650,8 +650,8 @@ test("media_unittests") {
   }
 
   if (is_win && cpu_arch == "x64") {
-    cflags += [ "/wd4267" ]  # TODO(wolenetz): Fix size_t to int trunctaion in win64. See
-                             # http://crbug.com/171009
+    cflags = [ "/wd4267" ]  # TODO(wolenetz): Fix size_t to int trunctaion in win64. See
+                            # http://crbug.com/171009
   }
 
   if (is_mac || is_ios) {
diff --git a/ppapi/BUILD.gn b/ppapi/BUILD.gn
index dd722c1..24827ab 100644
--- a/ppapi/BUILD.gn
+++ b/ppapi/BUILD.gn
@@ -29,15 +29,6 @@ source_set("ppapi_macros") {
 
 source_set("ppapi_cpp_objects") {
   sources = gypi_values.cpp_source_files
-
-  if (is_win) {
-    cflags = [ "/we4244" ]  # Implicit conversion, possible loss of data.
-  } else {
-    cflags = [
-      "-Wextra",
-      "-pedantic",
-    ]
-  }
 }
 
 source_set("ppapi_cpp") {
@@ -46,13 +37,6 @@ source_set("ppapi_cpp") {
     "cpp/ppp_entrypoints.cc",
   ]
 
-  if (is_posix) {
-    cflags = [
-      "-Wextra",
-      "-pedantic",
-    ]
-  }
-
   deps = [
     ":ppapi_c",
     ":ppapi_cpp_objects",
@@ -433,8 +417,6 @@ component("ppapi_shared") {
 
   if (is_mac) {
     libs = [ "QuartzCore.framework" ]
-  } else if (is_win) {
-    cflags = [ "/wd4267" ]  # size_t to int truncation.
   }
 }
 
@@ -750,10 +732,6 @@ component("ppapi_proxy") {
     "//ui/surface",
     blink_target,
   ]
-
-  if (is_win) {
-    cflags = [ "/wd4267" ]  # size_t to int truncation.
-  }
 }
 
 component("ppapi_host") {
diff --git a/ppapi/cpp/dev/file_chooser_dev.cc b/ppapi/cpp/dev/file_chooser_dev.cc
index b7124a1..2efb346 100644
--- a/ppapi/cpp/dev/file_chooser_dev.cc
+++ b/ppapi/cpp/dev/file_chooser_dev.cc
@@ -82,7 +82,7 @@ void FileChooser_Dev::CallbackConverter(void* user_data, int32_t result) {
   // number of items is 0.
   void* output_buf = data->output.GetDataBuffer(
       data->output.user_data,
-      selected_files.size(), sizeof(PP_Resource));
+      static_cast<uint32_t>(selected_files.size()), sizeof(PP_Resource));
   if (output_buf) {
     if (!selected_files.empty()) {
       memcpy(output_buf, &selected_files[0],
diff --git a/ppapi/cpp/dev/ime_input_event_dev.cc b/ppapi/cpp/dev/ime_input_event_dev.cc
index 9ddc16e..3396a39 100644
--- a/ppapi/cpp/dev/ime_input_event_dev.cc
+++ b/ppapi/cpp/dev/ime_input_event_dev.cc
@@ -61,7 +61,8 @@ IMEInputEvent_Dev::IMEInputEvent_Dev(
   uint32_t dummy = 0;
   PassRefFromConstructor(get_interface<PPB_IMEInputEvent_Dev_0_2>()->Create(
       instance.pp_instance(), type, time_stamp, text.pp_var(),
-      segment_offsets.empty() ? 0 : segment_offsets.size() - 1,
+      segment_offsets.empty() ? 0u :
+          static_cast<uint32_t>(segment_offsets.size() - 1),
       segment_offsets.empty() ? &dummy : &segment_offsets[0],
       target_segment, selection.first, selection.second));
 }
diff --git a/ppapi/cpp/dev/scriptable_object_deprecated.cc b/ppapi/cpp/dev/scriptable_object_deprecated.cc
index 1b701cb..19c4738 100644
--- a/ppapi/cpp/dev/scriptable_object_deprecated.cc
+++ b/ppapi/cpp/dev/scriptable_object_deprecated.cc
@@ -73,8 +73,8 @@ void GetAllPropertyNames(void* object,
 
   const PPB_Memory_Dev* memory_if = static_cast<const PPB_Memory_Dev*>(
       pp::Module::Get()->GetBrowserInterface(PPB_MEMORY_DEV_INTERFACE));
-  *properties = static_cast<PP_Var*>(
-      memory_if->MemAlloc(sizeof(PP_Var) * props.size()));
+  *properties = static_cast<PP_Var*>(memory_if->MemAlloc(
+      static_cast<uint32_t>(sizeof(PP_Var) * props.size())));
 
   for (size_t i = 0; i < props.size(); ++i)
     (*properties)[i] = props[i].Detach();
diff --git a/ppapi/cpp/dev/video_decoder_dev.cc b/ppapi/cpp/dev/video_decoder_dev.cc
index dcc3b5d..df34986 100644
--- a/ppapi/cpp/dev/video_decoder_dev.cc
+++ b/ppapi/cpp/dev/video_decoder_dev.cc
@@ -42,7 +42,7 @@ void VideoDecoder_Dev::AssignPictureBuffers(
   if (!has_interface<PPB_VideoDecoder_Dev>() || !pp_resource())
     return;
   get_interface<PPB_VideoDecoder_Dev>()->AssignPictureBuffers(
-      pp_resource(), buffers.size(), &buffers[0]);
+      pp_resource(), static_cast<uint32_t>(buffers.size()), &buffers[0]);
 }
 
 int32_t VideoDecoder_Dev::Decode(
diff --git a/ppapi/cpp/input_event.cc b/ppapi/cpp/input_event.cc
index 93385bf..90f41fa 100644
--- a/ppapi/cpp/input_event.cc
+++ b/ppapi/cpp/input_event.cc
@@ -364,7 +364,8 @@ IMEInputEvent::IMEInputEvent(
   uint32_t dummy = 0;
   PassRefFromConstructor(get_interface<PPB_IMEInputEvent_1_0>()->Create(
       instance.pp_instance(), type, time_stamp, text.pp_var(),
-      segment_offsets.empty() ? 0 : segment_offsets.size() - 1,
+      segment_offsets.empty() ? 0u :
+          static_cast<uint32_t>(segment_offsets.size() - 1),
       segment_offsets.empty() ? &dummy : &segment_offsets[0],
       target_segment, selection.first, selection.second));
 }
diff --git a/ppapi/cpp/private/content_decryptor_private.cc b/ppapi/cpp/private/content_decryptor_private.cc
index 76dc2f3..1e26661 100644
--- a/ppapi/cpp/private/content_decryptor_private.cc
+++ b/ppapi/cpp/private/content_decryptor_private.cc
@@ -329,7 +329,8 @@ void ContentDecryptor_Private::SessionKeysChange(
     pp::Var session_id_var(session_id);
     get_interface<PPB_ContentDecryptor_Private>()->SessionKeysChange(
         associated_instance_.pp_instance(), session_id_var.pp_var(),
-        PP_FromBool(has_additional_usable_key), key_information.size(),
+        PP_FromBool(has_additional_usable_key),
+        static_cast<uint32_t>(key_information.size()),
         key_information.empty() ? NULL : &key_information[0]);
   }
 }
diff --git a/ppapi/cpp/private/flash_clipboard.cc b/ppapi/cpp/private/flash_clipboard.cc
index 77e68ba..1fb5288 100644
--- a/ppapi/cpp/private/flash_clipboard.cc
+++ b/ppapi/cpp/private/flash_clipboard.cc
@@ -133,7 +133,7 @@ bool Clipboard::WriteData(
     rv = (get_interface<PPB_Flash_Clipboard_5_1>()->WriteData(
         instance.pp_instance(),
         clipboard_type,
-        data_items.size(),
+        static_cast<uint32_t>(data_items.size()),
         formats_ptr,
             data_items_ptr) == PP_OK);
   } else if (has_interface<PPB_Flash_Clipboard_5_0>()) {
@@ -155,7 +155,7 @@ bool Clipboard::WriteData(
     rv = (get_interface<PPB_Flash_Clipboard_5_0>()->WriteData(
         instance.pp_instance(),
         clipboard_type,
-        data_items.size(),
+        static_cast<uint32_t>(data_items.size()),
         formats_ptr,
         data_items_ptr) == PP_OK);
   } else if (has_interface<PPB_Flash_Clipboard_4_0>()) {
@@ -180,7 +180,7 @@ bool Clipboard::WriteData(
     rv = (get_interface<PPB_Flash_Clipboard_4_0>()->WriteData(
         instance.pp_instance(),
         clipboard_type,
-        data_items.size(),
+        static_cast<uint32_t>(data_items.size()),
         formats_ptr,
         data_items_ptr) == PP_OK);
   }
diff --git a/ppapi/examples/gamepad/gamepad.cc b/ppapi/examples/gamepad/gamepad.cc
index a94ccd4..d7f0053 100644
--- a/ppapi/examples/gamepad/gamepad.cc
+++ b/ppapi/examples/gamepad/gamepad.cc
@@ -108,7 +108,7 @@ class MyInstance : public pp::Instance {
       for (size_t i = 0; i < gamepad_data.items[0].buttons_length; ++i) {
         float button_val = gamepad_data.items[0].buttons[i];
         uint32_t colour = static_cast<uint32_t>((button_val * 192) + 63) << 24;
-        int x = i * 8 + 10;
+        int x = static_cast<int>(i) * 8 + 10;
         int y = 10;
         FillRect(&image, x - 3, y - 3, 7, 7, colour);
       }
diff --git a/ppapi/examples/ime/ime.cc b/ppapi/examples/ime/ime.cc
index 26c2f42..805d140 100644
--- a/ppapi/examples/ime/ime.cc
+++ b/ppapi/examples/ime/ime.cc
@@ -112,7 +112,8 @@ class TextFieldStatusNotifyingHandler : public TextFieldStatusHandler {
     textinput_control_.SetTextInputType(PP_TEXTINPUT_TYPE_NONE);
   }
   virtual void UpdateSelection(const std::string& text) {
-    textinput_control_.UpdateSurroundingText(text, 0, text.size());
+    textinput_control_.UpdateSurroundingText(
+        text, 0, static_cast<uint32_t>(text.size()));
   }
 
  private:
diff --git a/ppapi/examples/printing/printing.cc b/ppapi/examples/printing/printing.cc
index b87fc4f..37a7273 100644
--- a/ppapi/examples/printing/printing.cc
+++ b/ppapi/examples/printing/printing.cc
@@ -67,7 +67,7 @@ class MyInstance : public pp::Instance, public pp::Printing_Dev {
       const PP_PrintPageNumberRange_Dev* page_ranges,
       uint32_t page_range_count) {
     size_t pdf_len = strlen(pdf_data);
-    pp::Buffer_Dev buffer(this, pdf_len);
+    pp::Buffer_Dev buffer(this, static_cast<uint32_t>(pdf_len));
 
     memcpy(buffer.data(), pdf_data, pdf_len);
     return buffer;
diff --git a/ppapi/examples/video_decode/video_decode.cc b/ppapi/examples/video_decode/video_decode.cc
index ebfb80e..10e0536 100644
--- a/ppapi/examples/video_decode/video_decode.cc
+++ b/ppapi/examples/video_decode/video_decode.cc
@@ -662,11 +662,12 @@ Shader MyInstance::CreateProgram(const char* vertex_shader,
   // Create shader program.
   shader.program = gles2_if_->CreateProgram(context_->pp_resource());
   CreateShader(
-      shader.program, GL_VERTEX_SHADER, vertex_shader, strlen(vertex_shader));
+      shader.program, GL_VERTEX_SHADER, vertex_shader,
+      static_cast<uint32_t>(strlen(vertex_shader)));
   CreateShader(shader.program,
                GL_FRAGMENT_SHADER,
                fragment_shader,
-               strlen(fragment_shader));
+               static_cast<int>(strlen(fragment_shader)));
   gles2_if_->LinkProgram(context_->pp_resource(), shader.program);
   gles2_if_->UseProgram(context_->pp_resource(), shader.program);
   gles2_if_->Uniform1i(
diff --git a/ppapi/examples/video_decode/video_decode_dev.cc b/ppapi/examples/video_decode/video_decode_dev.cc
index d054e36..1cacb1b 100644
--- a/ppapi/examples/video_decode/video_decode_dev.cc
+++ b/ppapi/examples/video_decode/video_decode_dev.cc
@@ -341,11 +341,12 @@ void VideoDecodeDemoInstance::DecoderClient::DecodeNextNALU() {
   size_t start_pos = encoded_data_next_pos_to_decode_;
   size_t end_pos;
   GetNextNALUBoundary(start_pos, &end_pos);
-  pp::Buffer_Dev* buffer = new pp::Buffer_Dev(gles2_, end_pos - start_pos);
+  pp::Buffer_Dev* buffer = new pp::Buffer_Dev(
+      gles2_, static_cast<uint32_t>(end_pos - start_pos));
   PP_VideoBitstreamBuffer_Dev bitstream_buffer;
   int id = ++next_bitstream_buffer_id_;
   bitstream_buffer.id = id;
-  bitstream_buffer.size = end_pos - start_pos;
+  bitstream_buffer.size = static_cast<uint32_t>(end_pos - start_pos);
   bitstream_buffer.data = buffer->pp_resource();
   memcpy(buffer->data(), kData + start_pos, end_pos - start_pos);
   assert(bitstream_buffers_by_id_.insert(std::make_pair(id, buffer)).second);
@@ -637,9 +638,9 @@ Shader VideoDecodeDemoInstance::CreateProgram(const char* vertex_shader,
   // Create shader program.
   shader.program = gles2_if_->CreateProgram(context_->pp_resource());
   CreateShader(shader.program, GL_VERTEX_SHADER, vertex_shader,
-               strlen(vertex_shader));
+               static_cast<int>(strlen(vertex_shader)));
   CreateShader(shader.program, GL_FRAGMENT_SHADER, fragment_shader,
-               strlen(fragment_shader));
+               static_cast<int>(strlen(fragment_shader)));
   gles2_if_->LinkProgram(context_->pp_resource(), shader.program);
   gles2_if_->UseProgram(context_->pp_resource(), shader.program);
   gles2_if_->Uniform1i(
diff --git a/ppapi/ppapi_cpp.gypi b/ppapi/ppapi_cpp.gypi
index bf4d225..04d0d41 100644
--- a/ppapi/ppapi_cpp.gypi
+++ b/ppapi/ppapi_cpp.gypi
@@ -36,26 +36,6 @@
       'sources': [
         '<@(cpp_source_files)',
       ],
-      'conditions': [
-        ['OS=="win"', {
-          'msvs_settings': {
-            'VCCLCompilerTool': {
-              'AdditionalOptions': ['/we4244'],  # implicit conversion, possible loss of data
-            },
-          },
-          'msvs_disabled_warnings': [
-            4267,
-          ],
-        }],
-        ['OS=="linux"', {
-          'cflags': ['-Wextra', '-pedantic'],
-        }],
-        ['OS=="mac"', {
-          'xcode_settings': {
-            'WARNING_CFLAGS': ['-Wextra', '-pedantic'],
-           },
-        }],
-      ],
     },
     {
       # GN version: //ppapi:ppapi_cpp
@@ -72,16 +52,6 @@
         'cpp/module_embedder.h',
         'cpp/ppp_entrypoints.cc',
       ],
-      'conditions': [
-        ['OS=="linux"', {
-          'cflags': ['-Wextra', '-pedantic'],
-        }],
-        ['OS=="mac"', {
-          'xcode_settings': {
-            'WARNING_CFLAGS': ['-Wextra', '-pedantic'],
-           },
-        }]
-      ],
     },
     {
       # GN version: //ppapi:ppapi_internal_module
diff --git a/ppapi/ppapi_internal.gyp b/ppapi/ppapi_internal.gyp
index d96770e..4370640 100644
--- a/ppapi/ppapi_internal.gyp
+++ b/ppapi/ppapi_internal.gyp
@@ -85,8 +85,6 @@
           ],
         }],
       ],
-      # Disable c4267 warnings until we fix size_t to int truncations.
-      'msvs_disabled_warnings': [ 4267, ],
     },
   ],
   'conditions': [
@@ -144,8 +142,6 @@
                 '..',
             ],
           },
-          # Disable c4267 warnings until we fix size_t to int truncations.
-          'msvs_disabled_warnings': [ 4267, ],
           'conditions': [
             ['chrome_multiple_dll==1', {
               'dependencies': [
@@ -195,8 +191,6 @@
                 '..',
             ],
           },
-          # Disable c4267 warnings until we fix size_t to int truncations.
-          'msvs_disabled_warnings': [ 4267, ],
           'conditions': [
             ['chrome_multiple_dll==1', {
               'dependencies': [
diff --git a/ppapi/ppapi_tests.gypi b/ppapi/ppapi_tests.gypi
index d7bf047..63c3370 100644
--- a/ppapi/ppapi_tests.gypi
+++ b/ppapi/ppapi_tests.gypi
@@ -55,8 +55,6 @@
             '_CRT_NONSTDC_NO_DEPRECATE',
             '_SCL_SECURE_NO_DEPRECATE',
           ],
-          # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-          'msvs_disabled_warnings': [ 4267, ],
         }],
         ['OS=="mac"', {
           'mac_bundle': 1,
@@ -64,8 +62,6 @@
           'product_extension': 'plugin',
         }],
       ],
-      # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-      'msvs_disabled_warnings': [ 4267, ],
 # TODO(dmichael):  Figure out what is wrong with the script on Windows and add
 #                  it as an automated action.
 #      'actions': [
@@ -200,8 +196,6 @@
           ],
         }],
       ],
-      # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-      'msvs_disabled_warnings': [ 4267, ],
     },
     {
       'target_name': 'ppapi_example_skeleton',
@@ -262,8 +256,6 @@
       'sources': [
         'examples/gamepad/gamepad.cc',
       ],
-      # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-      'msvs_disabled_warnings': [ 4267, ],
     },
 
     {
@@ -345,8 +337,6 @@
       'sources': [
         'examples/ime/ime.cc',
       ],
-      # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-      'msvs_disabled_warnings': [ 4267, ],
     },
     {
       'target_name': 'ppapi_example_paint_manager',
@@ -456,8 +446,6 @@
         'examples/video_decode/video_decode.cc',
         'examples/video_decode/testdata.h',
       ],
-      # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-      'msvs_disabled_warnings': [ 4267, ],
     },
     {
       'target_name': 'ppapi_example_video_decode_dev',
@@ -473,8 +461,6 @@
         'examples/video_decode/video_decode_dev.cc',
         'examples/video_decode/testdata.h',
       ],
-      # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-      'msvs_disabled_warnings': [ 4267, ],
     },
     {
       'target_name': 'ppapi_example_vc',
@@ -529,8 +515,6 @@
       'sources': [
         'examples/printing/printing.cc',
       ],
-      # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-      'msvs_disabled_warnings': [ 4267, ],
     },
     {
       'target_name': 'ppapi_example_media_stream_audio',
diff --git a/ppapi/proxy/audio_input_resource.cc b/ppapi/proxy/audio_input_resource.cc
index 7f1f819..4a24255 100644
--- a/ppapi/proxy/audio_input_resource.cc
+++ b/ppapi/proxy/audio_input_resource.cc
@@ -6,6 +6,7 @@
 
 #include "base/bind.h"
 #include "base/logging.h"
+#include "base/numerics/safe_conversions.h"
 #include "ipc/ipc_platform_file.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/audio_bus.h"
@@ -249,7 +250,8 @@ void AudioInputResource::Run() {
   media::AudioInputBuffer* buffer =
       static_cast<media::AudioInputBuffer*>(shared_memory_->memory());
   const uint32_t audio_bus_size_bytes =
-      shared_memory_size_ - sizeof(media::AudioInputBufferParameters);
+      base::checked_cast<uint32_t>(shared_memory_size_ -
+                                   sizeof(media::AudioInputBufferParameters));
 
   while (true) {
     int pending_data = 0;
diff --git a/ppapi/proxy/device_enumeration_resource_helper.cc b/ppapi/proxy/device_enumeration_resource_helper.cc
index 18b1939..32a4e1db 100644
--- a/ppapi/proxy/device_enumeration_resource_helper.cc
+++ b/ppapi/proxy/device_enumeration_resource_helper.cc
@@ -146,7 +146,7 @@ void DeviceEnumerationResourceHelper::OnPluginMsgNotifyDeviceChange(
   CHECK(monitor_callback_.get());
 
   scoped_ptr<PP_Resource[]> elements;
-  uint32_t size = devices.size();
+  uint32_t size = static_cast<uint32_t>(devices.size());
   if (size > 0) {
     elements.reset(new PP_Resource[size]);
     for (size_t index = 0; index < size; ++index) {
diff --git a/ppapi/proxy/file_ref_resource.cc b/ppapi/proxy/file_ref_resource.cc
index 098ef5f..ee56969 100644
--- a/ppapi/proxy/file_ref_resource.cc
+++ b/ppapi/proxy/file_ref_resource.cc
@@ -4,6 +4,7 @@
 
 #include "ppapi/proxy/file_ref_resource.h"
 
+#include "base/numerics/safe_conversions.h"
 #include "ppapi/c/pp_directory_entry.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_resource.h"
@@ -29,7 +30,7 @@ FileRefResource::FileRefResource(
   if (uses_internal_paths()) {
     // If path ends with a slash, then normalize it away unless path is
     // the root path.
-    int path_size = create_info_.internal_path.size();
+    int path_size = base::checked_cast<int>(create_info_.internal_path.size());
     if (path_size > 1 && create_info_.internal_path.at(path_size - 1) == '/')
       create_info_.internal_path.erase(path_size - 1, 1);
 
diff --git a/ppapi/proxy/flash_clipboard_resource.cc b/ppapi/proxy/flash_clipboard_resource.cc
index 2b665bf..28df94c 100644
--- a/ppapi/proxy/flash_clipboard_resource.cc
+++ b/ppapi/proxy/flash_clipboard_resource.cc
@@ -4,6 +4,7 @@
 
 #include "ppapi/proxy/flash_clipboard_resource.h"
 
+#include "base/numerics/safe_conversions.h"
 #include "ipc/ipc_message.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/proxy/ppapi_messages.h"
@@ -53,7 +54,7 @@ PP_Var ClipboardStringToPPVar(int32_t format,
   } else {
     // All other formats are expected to be array buffers.
     return PpapiGlobals::Get()->GetVarTracker()->MakeArrayBufferPPVar(
-        string.size(), string.data());
+        base::checked_cast<uint32_t>(string.size()), string.data());
   }
 }
 }  // namespace
diff --git a/ppapi/proxy/pdf_resource.cc b/ppapi/proxy/pdf_resource.cc
index 7d20d91..e9d3ae8 100644
--- a/ppapi/proxy/pdf_resource.cc
+++ b/ppapi/proxy/pdf_resource.cc
@@ -89,7 +89,7 @@ void PDFResource::SearchString(const unsigned short* input_string,
 
   std::vector<PP_PrivateFindResult> pp_results;
   while (match_start != USEARCH_DONE) {
-    size_t matched_length = usearch_getMatchedLength(searcher);
+    int32_t matched_length = usearch_getMatchedLength(searcher);
     PP_PrivateFindResult result;
     result.start_index = match_start;
     result.length = matched_length;
@@ -98,7 +98,7 @@ void PDFResource::SearchString(const unsigned short* input_string,
     DCHECK(status == U_ZERO_ERROR);
   }
 
-  *count = pp_results.size();
+  *count = static_cast<uint32_t>(pp_results.size());
   if (*count) {
     *results = reinterpret_cast<PP_PrivateFindResult*>(malloc(
         *count * sizeof(PP_PrivateFindResult)));
diff --git a/ppapi/proxy/platform_verification_private_resource.cc b/ppapi/proxy/platform_verification_private_resource.cc
index 76d5148..27804d3 100644
--- a/ppapi/proxy/platform_verification_private_resource.cc
+++ b/ppapi/proxy/platform_verification_private_resource.cc
@@ -88,10 +88,11 @@ void PlatformVerificationPrivateResource::OnChallengePlatformReply(
   if (params.result() == PP_OK) {
     *(output_params.signed_data) =
         (PpapiGlobals::Get()->GetVarTracker()->MakeArrayBufferVar(
-            raw_signed_data.size(), &raw_signed_data.front()))->GetPPVar();
+            static_cast<uint32_t>(raw_signed_data.size()),
+            &raw_signed_data.front()))->GetPPVar();
     *(output_params.signed_data_signature) =
         (PpapiGlobals::Get()->GetVarTracker()->MakeArrayBufferVar(
-            raw_signed_data_signature.size(),
+            static_cast<uint32_t>(raw_signed_data_signature.size()),
             &raw_signed_data_signature.front()))->GetPPVar();
     *(output_params.platform_key_certificate) =
         (new StringVar(raw_platform_key_certificate))->GetPPVar();
diff --git a/ppapi/proxy/ppapi_command_buffer_proxy.cc b/ppapi/proxy/ppapi_command_buffer_proxy.cc
index 571210e..644e79e 100644
--- a/ppapi/proxy/ppapi_command_buffer_proxy.cc
+++ b/ppapi/proxy/ppapi_command_buffer_proxy.cc
@@ -4,6 +4,7 @@
 
 #include "ppapi/proxy/ppapi_command_buffer_proxy.h"
 
+#include "base/numerics/safe_conversions.h"
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/proxy/proxy_channel.h"
 #include "ppapi/shared_impl/api_id.h"
@@ -122,7 +123,8 @@ scoped_refptr<gpu::Buffer> PpapiCommandBufferProxy::CreateTransferBuffer(
   ppapi::proxy::SerializedHandle handle(
       ppapi::proxy::SerializedHandle::SHARED_MEMORY);
   if (!Send(new PpapiHostMsg_PPBGraphics3D_CreateTransferBuffer(
-            ppapi::API_ID_PPB_GRAPHICS_3D, resource_, size, id, &handle))) {
+            ppapi::API_ID_PPB_GRAPHICS_3D, resource_,
+            base::checked_cast<uint32_t>(size), id, &handle))) {
     return NULL;
   }
 
diff --git a/ppapi/proxy/ppb_graphics_3d_proxy.cc b/ppapi/proxy/ppb_graphics_3d_proxy.cc
index 7cd2b88..6b49914 100644
--- a/ppapi/proxy/ppb_graphics_3d_proxy.cc
+++ b/ppapi/proxy/ppb_graphics_3d_proxy.cc
@@ -4,6 +4,7 @@
 
 #include "ppapi/proxy/ppb_graphics_3d_proxy.h"
 
+#include "base/numerics/safe_conversions.h"
 #include "gpu/command_buffer/client/gles2_implementation.h"
 #include "gpu/command_buffer/common/command_buffer.h"
 #include "ppapi/c/pp_errors.h"
@@ -315,7 +316,7 @@ void PPB_Graphics3D_Proxy::OnMsgCreateTransferBuffer(
     DCHECK(backing && backing->shared_memory());
     transfer_buffer->set_shmem(
         TransportSHMHandle(dispatcher(), backing->shared_memory()->handle()),
-        buffer->size());
+        base::checked_cast<uint32_t>(buffer->size()));
   } else {
     *id = -1;
   }
diff --git a/ppapi/proxy/ppb_instance_proxy.cc b/ppapi/proxy/ppb_instance_proxy.cc
index f8b8ac9..2897757 100644
--- a/ppapi/proxy/ppb_instance_proxy.cc
+++ b/ppapi/proxy/ppb_instance_proxy.cc
@@ -5,6 +5,7 @@
 #include "ppapi/proxy/ppb_instance_proxy.h"
 
 #include "base/memory/ref_counted.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/stl_util.h"
 #include "build/build_config.h"
 #include "media/base/limits.h"
@@ -1302,7 +1303,8 @@ void PPB_Instance_Proxy::OnHostMsgSessionKeysChange(
                                StringVar::StringToPPVar(session_id));
     enter.functions()->SessionKeysChange(
         instance, session_id_var.get(), has_additional_usable_key,
-        key_information.size(), vector_as_array(&key_information));
+        base::checked_cast<uint32_t>(key_information.size()),
+        vector_as_array(&key_information));
   }
 }
 
diff --git a/ppapi/proxy/ppb_testing_proxy.cc b/ppapi/proxy/ppb_testing_proxy.cc
index 0dbab0b..606cdc31 100644
--- a/ppapi/proxy/ppb_testing_proxy.cc
+++ b/ppapi/proxy/ppb_testing_proxy.cc
@@ -112,7 +112,7 @@ uint32_t GetLiveVars(PP_Var live_vars[], uint32_t array_size) {
        i < std::min(static_cast<size_t>(array_size), vars.size());
        ++i)
     live_vars[i] = vars[i];
-  return vars.size();
+  return static_cast<uint32_t>(vars.size());
 }
 
 void SetMinimumArrayBufferSizeForShmem(PP_Instance instance,
diff --git a/ppapi/proxy/ppb_var_unittest.cc b/ppapi/proxy/ppb_var_unittest.cc
index 5e25379..98b6428 100644
--- a/ppapi/proxy/ppb_var_unittest.cc
+++ b/ppapi/proxy/ppb_var_unittest.cc
@@ -33,7 +33,7 @@ class PPB_VarTest : public PluginProxyTest {
         ppb_var_(ppapi::PPB_Var_Shared::GetVarInterface1_2()) {
     // Set the value of test_strings_[i] to "i".
     for (size_t i = 0; i < kNumStrings; ++i)
-      test_strings_[i] = base::IntToString(i);
+      test_strings_[i] = base::IntToString(static_cast<int>(i));
   }
  protected:
   std::vector<std::string> test_strings_;
@@ -44,8 +44,9 @@ class PPB_VarTest : public PluginProxyTest {
 // Test basic String operations.
 TEST_F(PPB_VarTest, Strings) {
   for (size_t i = 0; i < kNumStrings; ++i) {
-    vars_[i] = ppb_var_->VarFromUtf8(test_strings_[i].c_str(),
-                                     test_strings_[i].length());
+    vars_[i] = ppb_var_->VarFromUtf8(
+        test_strings_[i].c_str(),
+        static_cast<uint32_t>(test_strings_[i].length()));
     EXPECT_EQ(test_strings_[i], VarToString(vars_[i], ppb_var_));
   }
   // At this point, they should each have a ref count of 1. Add some more.
@@ -104,8 +105,9 @@ class CreateVarThreadDelegate : public base::PlatformThread::Delegate {
   virtual void ThreadMain() {
     const PPB_Var* ppb_var = ppapi::PPB_Var_Shared::GetVarInterface1_2();
     for (size_t i = 0; i < size_; ++i) {
-      vars_out_[i] = ppb_var->VarFromUtf8(strings_in_[i].c_str(),
-                                          strings_in_[i].length());
+      vars_out_[i] = ppb_var->VarFromUtf8(
+          strings_in_[i].c_str(),
+          static_cast<uint32_t>(strings_in_[i].length()));
       strings_out_[i] = VarToString(vars_out_[i], ppb_var);
     }
   }
diff --git a/ppapi/proxy/ppb_video_decoder_proxy.cc b/ppapi/proxy/ppb_video_decoder_proxy.cc
index 7699c84..779294f 100644
--- a/ppapi/proxy/ppb_video_decoder_proxy.cc
+++ b/ppapi/proxy/ppb_video_decoder_proxy.cc
@@ -5,6 +5,7 @@
 #include "ppapi/proxy/ppb_video_decoder_proxy.h"
 
 #include "base/logging.h"
+#include "base/numerics/safe_conversions.h"
 #include "gpu/command_buffer/client/gles2_implementation.h"
 #include "ppapi/proxy/enter_proxy.h"
 #include "ppapi/proxy/plugin_dispatcher.h"
@@ -247,7 +248,8 @@ void PPB_VideoDecoder_Proxy::OnMsgAssignPictureBuffers(
   EnterHostFromHostResource<PPB_VideoDecoder_Dev_API> enter(decoder);
   if (enter.succeeded() && !buffers.empty()) {
     const PP_PictureBuffer_Dev* buffer_array = &buffers.front();
-    enter.object()->AssignPictureBuffers(buffers.size(), buffer_array);
+    enter.object()->AssignPictureBuffers(
+        base::checked_cast<uint32_t>(buffers.size()), buffer_array);
   }
 }
 
diff --git a/ppapi/proxy/ppp_content_decryptor_private_proxy.cc b/ppapi/proxy/ppp_content_decryptor_private_proxy.cc
index 91ea370..329714b 100644
--- a/ppapi/proxy/ppp_content_decryptor_private_proxy.cc
+++ b/ppapi/proxy/ppp_content_decryptor_private_proxy.cc
@@ -544,8 +544,9 @@ void PPP_ContentDecryptor_Private_Proxy::OnMsgSetServerCertificate(
         ScopedPPVar::PassRef(),
         PpapiGlobals::Get()
             ->GetVarTracker()
-            ->MakeArrayBufferPPVar(server_certificate.size(),
-                                   &server_certificate[0]));
+            ->MakeArrayBufferPPVar(
+                static_cast<uint32_t>(server_certificate.size()),
+                &server_certificate[0]));
     CallWhileUnlocked(ppp_decryptor_impl_->SetServerCertificate,
                       instance,
                       promise_id,
diff --git a/ppapi/proxy/ppp_instance_proxy_unittest.cc b/ppapi/proxy/ppp_instance_proxy_unittest.cc
index e2df26e..18ec919 100644
--- a/ppapi/proxy/ppp_instance_proxy_unittest.cc
+++ b/ppapi/proxy/ppp_instance_proxy_unittest.cc
@@ -140,7 +140,7 @@ TEST_F(PPP_Instance_ProxyTest, PPPInstance1_0) {
     argn_to_pass.push_back(expected_argn[i].c_str());
     argv_to_pass.push_back(expected_argv[i].c_str());
   }
-  uint32_t expected_argc = expected_argn.size();
+  uint32_t expected_argc = static_cast<uint32_t>(expected_argn.size());
   bool_to_return = PP_TRUE;
   ResetReceived();
   // Tell the host resource tracker about the instance.
diff --git a/ppapi/proxy/ppp_printing_proxy.cc b/ppapi/proxy/ppp_printing_proxy.cc
index 7b2ae55..780b91f 100644
--- a/ppapi/proxy/ppp_printing_proxy.cc
+++ b/ppapi/proxy/ppp_printing_proxy.cc
@@ -6,6 +6,7 @@
 
 #include <string.h>
 
+#include "base/numerics/safe_conversions.h"
 #include "ppapi/c/dev/ppp_printing_dev.h"
 #include "ppapi/proxy/host_dispatcher.h"
 #include "ppapi/proxy/plugin_dispatcher.h"
@@ -180,7 +181,7 @@ void PPP_Printing_Proxy::OnPluginMsgPrintPages(
 
   PP_Resource plugin_resource = CallWhileUnlocked(
       ppp_printing_impl_->PrintPages,
-      instance, &pages[0], pages.size());
+      instance, &pages[0], base::checked_cast<uint32_t>(pages.size()));
   ResourceTracker* resource_tracker = PpapiGlobals::Get()->GetResourceTracker();
   Resource* resource_object = resource_tracker->GetResource(plugin_resource);
   if (!resource_object)
diff --git a/ppapi/proxy/raw_var_data_unittest.cc b/ppapi/proxy/raw_var_data_unittest.cc
index 7dba345..3539d675 100644
--- a/ppapi/proxy/raw_var_data_unittest.cc
+++ b/ppapi/proxy/raw_var_data_unittest.cc
@@ -96,7 +96,7 @@ TEST_F(RawVarDataTest, StringTest) {
 TEST_F(RawVarDataTest, ArrayBufferTest) {
   std::string data = "hello world!";
   PP_Var var = PpapiGlobals::Get()->GetVarTracker()->MakeArrayBufferPPVar(
-      data.size(), data.data());
+      static_cast<uint32_t>(data.size()), data.data());
   EXPECT_TRUE(WriteReadAndCompare(var));
   var = PpapiGlobals::Get()->GetVarTracker()->MakeArrayBufferPPVar(
       0, static_cast<void*>(NULL));
@@ -113,25 +113,25 @@ TEST_F(RawVarDataTest, DictionaryArrayTest) {
   size_t index = 0;
 
   // Array with primitives.
-  array->Set(index++, PP_MakeUndefined());
-  array->Set(index++, PP_MakeNull());
-  array->Set(index++, PP_MakeInt32(100));
-  array->Set(index++, PP_MakeBool(PP_FALSE));
-  array->Set(index++, PP_MakeDouble(0.123));
+  array->Set(static_cast<uint32_t>(index++), PP_MakeUndefined());
+  array->Set(static_cast<uint32_t>(index++), PP_MakeNull());
+  array->Set(static_cast<uint32_t>(index++), PP_MakeInt32(100));
+  array->Set(static_cast<uint32_t>(index++), PP_MakeBool(PP_FALSE));
+  array->Set(static_cast<uint32_t>(index++), PP_MakeDouble(0.123));
   EXPECT_TRUE(WriteReadAndCompare(array->GetPPVar()));
 
   // Array with 2 references to the same string.
   ScopedPPVar release_string(
       ScopedPPVar::PassRef(), StringVar::StringToPPVar("abc"));
-  array->Set(index++, release_string.get());
-  array->Set(index++, release_string.get());
+  array->Set(static_cast<uint32_t>(index++), release_string.get());
+  array->Set(static_cast<uint32_t>(index++), release_string.get());
   EXPECT_TRUE(WriteReadAndCompare(array->GetPPVar()));
 
   // Array with nested array that references the same string.
   scoped_refptr<ArrayVar> array2(new ArrayVar);
   ScopedPPVar release_array2(ScopedPPVar::PassRef(), array2->GetPPVar());
   array2->Set(0, release_string.get());
-  array->Set(index++, release_array2.get());
+  array->Set(static_cast<uint32_t>(index++), release_array2.get());
   EXPECT_TRUE(WriteReadAndCompare(array->GetPPVar()));
 
   // Empty dictionary.
@@ -162,7 +162,7 @@ TEST_F(RawVarDataTest, DictionaryArrayTest) {
   EXPECT_TRUE(WriteReadAndCompare(dictionary->GetPPVar()));
 
   // Array with dictionary.
-  array->Set(index++, release_dictionary.get());
+  array->Set(static_cast<uint32_t>(index++), release_dictionary.get());
   EXPECT_TRUE(WriteReadAndCompare(array->GetPPVar()));
 
   // Array with dictionary with array.
@@ -180,10 +180,10 @@ TEST_F(RawVarDataTest, DictionaryArrayTest) {
   dictionary->DeleteWithStringKey("10");
 
   // Array with self references.
-  array->Set(index, release_array.get());
+  array->Set(static_cast<uint32_t>(index), release_array.get());
   ASSERT_FALSE(WriteAndRead(release_array.get(), &result));
   // Break the self reference.
-  array->Set(index, PP_MakeUndefined());
+  array->Set(static_cast<uint32_t>(index), PP_MakeUndefined());
 }
 
 TEST_F(RawVarDataTest, ResourceTest) {
diff --git a/ppapi/proxy/serialized_var_unittest.cc b/ppapi/proxy/serialized_var_unittest.cc
index 206830e..d88c848 100644
--- a/ppapi/proxy/serialized_var_unittest.cc
+++ b/ppapi/proxy/serialized_var_unittest.cc
@@ -258,7 +258,7 @@ TEST_F(SerializedVarTest, PluginVectorReceiveInput) {
 
     // Take a reference to a string and then release it. Make sure no messages
     // are sent.
-    uint32_t old_message_count = sink().message_count();
+    uint32_t old_message_count = static_cast<uint32_t>(sink().message_count());
     var_tracker().AddRefVar(plugin_objects[1]);
     EXPECT_EQ(2, var_tracker().GetRefCountForObject(plugin_objects[1]));
     var_tracker().ReleaseVar(plugin_objects[1]);
diff --git a/ppapi/proxy/url_loader_resource.cc b/ppapi/proxy/url_loader_resource.cc
index 73bdb23..0697e90 100644
--- a/ppapi/proxy/url_loader_resource.cc
+++ b/ppapi/proxy/url_loader_resource.cc
@@ -5,6 +5,7 @@
 #include "ppapi/proxy/url_loader_resource.h"
 
 #include "base/logging.h"
+#include "base/numerics/safe_conversions.h"
 #include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/ppb_url_loader.h"
@@ -374,7 +375,7 @@ void URLLoaderResource::SaveResponseInfo(const URLResponseInfoData& data) {
       connection(), pp_instance(), data, body_as_file_ref);
 }
 
-size_t URLLoaderResource::FillUserBuffer() {
+int32_t URLLoaderResource::FillUserBuffer() {
   DCHECK(user_buffer_);
   DCHECK(user_buffer_size_);
 
@@ -393,7 +394,7 @@ size_t URLLoaderResource::FillUserBuffer() {
   // Reset for next time.
   user_buffer_ = NULL;
   user_buffer_size_ = 0;
-  return bytes_to_copy;
+  return base::checked_cast<int32_t>(bytes_to_copy);
 }
 
 }  // namespace proxy
diff --git a/ppapi/proxy/url_loader_resource.h b/ppapi/proxy/url_loader_resource.h
index 4986932..457dd4a 100644
--- a/ppapi/proxy/url_loader_resource.h
+++ b/ppapi/proxy/url_loader_resource.h
@@ -114,7 +114,7 @@ class PPAPI_PROXY_EXPORT URLLoaderResource
   // necessary. This does not issue any callbacks.
   void SaveResponseInfo(const URLResponseInfoData& data);
 
-  size_t FillUserBuffer();
+  int32_t FillUserBuffer();
 
   Mode mode_;
   URLRequestInfoData request_data_;
diff --git a/ppapi/proxy/video_capture_resource.cc b/ppapi/proxy/video_capture_resource.cc
index 5c95ed8..ca69d38 100644
--- a/ppapi/proxy/video_capture_resource.cc
+++ b/ppapi/proxy/video_capture_resource.cc
@@ -166,7 +166,7 @@ void VideoCaptureResource::OnPluginMsgOnDeviceInfo(
                     pp_instance(),
                     pp_resource(),
                     &info,
-                    buffers.size(),
+                    static_cast<uint32_t>(buffers.size()),
                     resources.get());
 
   for (size_t i = 0; i < buffers.size(); ++i)
diff --git a/ppapi/proxy/websocket_resource.cc b/ppapi/proxy/websocket_resource.cc
index d03121a..bc4e853 100644
--- a/ppapi/proxy/websocket_resource.cc
+++ b/ppapi/proxy/websocket_resource.cc
@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "base/bind.h"
+#include "base/numerics/safe_conversions.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/proxy/dispatch_reply_message.h"
 #include "ppapi/proxy/ppapi_messages.h"
@@ -424,7 +425,7 @@ void WebSocketResource::OnPluginMsgReceiveBinaryReply(
   // Append received data to queue.
   scoped_refptr<Var> message_var(
       PpapiGlobals::Get()->GetVarTracker()->MakeArrayBufferVar(
-          message.size(),
+          base::checked_cast<uint32_t>(message.size()),
           &message.front()));
   received_messages_.push(message_var);
 
diff --git a/ppapi/proxy/websocket_resource_unittest.cc b/ppapi/proxy/websocket_resource_unittest.cc
index 8c300ce..f65c2a5 100644
--- a/ppapi/proxy/websocket_resource_unittest.cc
+++ b/ppapi/proxy/websocket_resource_unittest.cc
@@ -47,7 +47,8 @@ PP_CompletionCallback MakeCallback() {
 PP_Var MakeStringVar(const std::string& string) {
   if (!ppb_var_)
     ppb_var_ = ppapi::PPB_Var_Shared::GetVarInterface1_2();
-  return ppb_var_->VarFromUtf8(string.c_str(), string.length());
+  return ppb_var_->VarFromUtf8(string.c_str(),
+                               static_cast<uint32_t>(string.length()));
 }
 
 }  // namespace
diff --git a/ppapi/shared_impl/array_writer.h b/ppapi/shared_impl/array_writer.h
index fce10e4..1d2608a 100644
--- a/ppapi/shared_impl/array_writer.h
+++ b/ppapi/shared_impl/array_writer.h
@@ -74,7 +74,8 @@ class PPAPI_SHARED_EXPORT ArrayWriter {
   // comment of StoreArray() for detail.
   template <typename T>
   bool StoreVector(const std::vector<T>& input) {
-    return StoreArray(input.size() ? &input[0] : NULL, input.size());
+    return StoreArray(input.size() ? &input[0] : NULL,
+                      static_cast<uint32_t>(input.size()));
   }
 
   // Stores the given vector of resources as PP_Resources to the output vector,
diff --git a/ppapi/shared_impl/flash_clipboard_format_registry.cc b/ppapi/shared_impl/flash_clipboard_format_registry.cc
index 89a051e..fa43478 100644
--- a/ppapi/shared_impl/flash_clipboard_format_registry.cc
+++ b/ppapi/shared_impl/flash_clipboard_format_registry.cc
@@ -6,6 +6,8 @@
 
 #include <cctype>
 
+#include "base/numerics/safe_conversions.h"
+
 namespace ppapi {
 
 namespace {
@@ -43,7 +45,8 @@ uint32_t FlashClipboardFormatRegistry::RegisterFormat(
       custom_formats_.size() > kMaxNumFormats) {
     return PP_FLASH_CLIPBOARD_FORMAT_INVALID;
   }
-  uint32_t key = kFirstCustomFormat + custom_formats_.size();
+  uint32_t key = kFirstCustomFormat +
+                 base::checked_cast<uint32_t>(custom_formats_.size());
   custom_formats_[key] = format_name;
   return key;
 }
diff --git a/ppapi/tests/test_file_io.cc b/ppapi/tests/test_file_io.cc
index 5b26804..8783905 100644
--- a/ppapi/tests/test_file_io.cc
+++ b/ppapi/tests/test_file_io.cc
@@ -150,7 +150,7 @@ int32_t WriteEntireBuffer(PP_Instance instance,
   TestCompletionCallback callback(instance, callback_type);
   int32_t write_offset = offset;
   const char* buf = data.c_str();
-  int32_t size = data.size();
+  int32_t size = static_cast<int32_t>(data.size());
 
   while (write_offset < offset + size) {
     callback.WaitForResult(file_io->Write(write_offset,
@@ -781,7 +781,7 @@ std::string TestFileIO::TestParallelReads() {
 
   // Parallel read operations.
   const char* border = "__border__";
-  const int32_t border_size = strlen(border);
+  const int32_t border_size = static_cast<int32_t>(strlen(border));
 
   TestCompletionCallback callback_1(instance_->pp_instance(), callback_type());
   int32_t read_offset_1 = 0;
@@ -865,12 +865,12 @@ std::string TestFileIO::TestParallelWrites() {
   TestCompletionCallback callback_1(instance_->pp_instance(), callback_type());
   int32_t write_offset_1 = 0;
   const char* buf_1 = "abc";
-  int32_t size_1 = strlen(buf_1);
+  int32_t size_1 = static_cast<int32_t>(strlen(buf_1));
 
   TestCompletionCallback callback_2(instance_->pp_instance(), callback_type());
   int32_t write_offset_2 = size_1;
   const char* buf_2 = "defghijkl";
-  int32_t size_2 = strlen(buf_2);
+  int32_t size_2 = static_cast<int32_t>(strlen(buf_2));
 
   int32_t rv_1 = PP_OK;
   int32_t rv_2 = PP_OK;
@@ -879,7 +879,8 @@ std::string TestFileIO::TestParallelWrites() {
       // Copy the buffer so we can erase it below.
       std::string str_1(buf_1);
       rv_1 = file_io.Write(
-          write_offset_1, &str_1[0], str_1.size(), callback_1.GetCallback());
+          write_offset_1, &str_1[0], static_cast<int32_t>(str_1.size()),
+          callback_1.GetCallback());
       // Erase the buffer to test that async writes copy it.
       std::fill(str_1.begin(), str_1.end(), 0);
     }
@@ -887,7 +888,8 @@ std::string TestFileIO::TestParallelWrites() {
       // Copy the buffer so we can erase it below.
       std::string str_2(buf_2);
       rv_2 = file_io.Write(
-          write_offset_2, &str_2[0], str_2.size(), callback_2.GetCallback());
+          write_offset_2, &str_2[0], static_cast<int32_t>(str_2.size()),
+          callback_2.GetCallback());
       // Erase the buffer to test that async writes copy it.
       std::fill(str_2.begin(), str_2.end(), 0);
     }
@@ -951,7 +953,8 @@ std::string TestFileIO::TestNotAllowMixedReadWrite() {
   TestCompletionCallback callback_1(instance_->pp_instance(), PP_REQUIRED);
   int32_t write_offset_1 = 0;
   const char* buf_1 = "mnopqrstuvw";
-  int32_t rv_1 = file_io.Write(write_offset_1, buf_1, strlen(buf_1),
+  int32_t rv_1 = file_io.Write(write_offset_1, buf_1,
+                               static_cast<int32_t>(strlen(buf_1)),
                                callback_1.GetCallback());
   ASSERT_EQ(PP_OK_COMPLETIONPENDING, rv_1);
 
@@ -966,7 +969,8 @@ std::string TestFileIO::TestNotAllowMixedReadWrite() {
   CHECK_CALLBACK_BEHAVIOR(callback_1);
 
   // Cannot query while a write is pending.
-  rv_1 = file_io.Write(write_offset_1, buf_1, strlen(buf_1),
+  rv_1 = file_io.Write(write_offset_1, buf_1,
+                       static_cast<int32_t>(strlen(buf_1)),
                        callback_1.GetCallback());
   ASSERT_EQ(PP_OK_COMPLETIONPENDING, rv_1);
   PP_FileInfo info;
@@ -977,7 +981,8 @@ std::string TestFileIO::TestNotAllowMixedReadWrite() {
   CHECK_CALLBACK_BEHAVIOR(callback_1);
 
   // Cannot touch while a write is pending.
-  rv_1 = file_io.Write(write_offset_1, buf_1, strlen(buf_1),
+  rv_1 = file_io.Write(write_offset_1, buf_1,
+                       static_cast<int32_t>(strlen(buf_1)),
                        callback_1.GetCallback());
   ASSERT_EQ(PP_OK_COMPLETIONPENDING, rv_1);
   callback_2.WaitForResult(file_io.Touch(1234.0, 5678.0,
@@ -988,7 +993,8 @@ std::string TestFileIO::TestNotAllowMixedReadWrite() {
   CHECK_CALLBACK_BEHAVIOR(callback_1);
 
   // Cannot set length while a write is pending.
-  rv_1 = file_io.Write(write_offset_1, buf_1, strlen(buf_1),
+  rv_1 = file_io.Write(write_offset_1, buf_1,
+                       static_cast<int32_t>(strlen(buf_1)),
                        callback_1.GetCallback());
   ASSERT_EQ(PP_OK_COMPLETIONPENDING, rv_1);
   callback_2.WaitForResult(file_io.SetLength(123, callback_2.GetCallback()));
@@ -1038,7 +1044,7 @@ std::string TestFileIO::TestRequestOSFileHandle() {
 
   // Check write(2) for the native FD.
   const std::string msg = "foobar";
-  ssize_t cnt = write(fd, msg.data(), msg.size());
+  ssize_t cnt = write(fd, msg.data(), static_cast<unsigned>(msg.size()));
   if (cnt < 0)
     return ReportError("write for native FD returned error", errno);
   if (cnt != static_cast<ssize_t>(msg.size()))
@@ -1059,7 +1065,7 @@ std::string TestFileIO::TestRequestOSFileHandle() {
 
   // Check read(2) for the native FD.
   std::string buf(msg.size(), '\0');
-  cnt = read(fd, &buf[0], msg.size());
+  cnt = read(fd, &buf[0], static_cast<unsigned>(msg.size()));
   if (cnt < 0)
     return ReportError("read for native FD returned error", errno);
   if (cnt != static_cast<ssize_t>(msg.size()))
@@ -1274,8 +1280,8 @@ std::string TestFileIO::TestMmap() {
 }
 
 std::string TestFileIO::MatchOpenExpectations(pp::FileSystem* file_system,
-                                              size_t open_flags,
-                                              size_t expectations) {
+                                              int32_t open_flags,
+                                              int32_t expectations) {
   std::string bad_argument =
       "TestFileIO::MatchOpenExpectations has invalid input arguments.";
   bool invalid_combination = !!(expectations & INVALID_FLAG_COMBINATION);
diff --git a/ppapi/tests/test_file_io.h b/ppapi/tests/test_file_io.h
index 3cc0095..e01abcf 100644
--- a/ppapi/tests/test_file_io.h
+++ b/ppapi/tests/test_file_io.h
@@ -57,8 +57,8 @@ class TestFileIO : public TestCase {
   // 2) (DONT_)?CREATE_IF_DOESNT_EXIST | (DONT_)?OPEN_IF_EXISTS |
   //    (DONT_)?TRUNCATE_IF_EXISTS
   std::string MatchOpenExpectations(pp::FileSystem* file_system,
-                                    size_t open_flags,
-                                    size_t expectations);
+                                    int32_t open_flags,
+                                    int32_t expectations);
 };
 
 #endif  // PAPPI_TESTS_TEST_FILE_IO_H_
diff --git a/ppapi/tests/test_file_mapping.cc b/ppapi/tests/test_file_mapping.cc
index 4e879b5..ee10e18 100644
--- a/ppapi/tests/test_file_mapping.cc
+++ b/ppapi/tests/test_file_mapping.cc
@@ -55,7 +55,7 @@ int32_t WriteEntireBuffer(PP_Instance instance,
   TestCompletionCallback callback(instance, callback_type);
   int32_t write_offset = offset;
   const char* buf = data.c_str();
-  int32_t size = data.size();
+  int32_t size = static_cast<int32_t>(data.size());
 
   while (write_offset < offset + size) {
     callback.WaitForResult(file_io->Write(write_offset,
diff --git a/ppapi/tests/test_flash_clipboard.cc b/ppapi/tests/test_flash_clipboard.cc
index 505399d..e94cb7f 100644
--- a/ppapi/tests/test_flash_clipboard.cc
+++ b/ppapi/tests/test_flash_clipboard.cc
@@ -151,7 +151,7 @@ std::string TestFlashClipboard::TestReadWriteRTF() {
         "{\\rtf1\\ansi{\\fonttbl\\f0\\fswiss Helvetica;}\\f0\\pard\n"
         "This is some {\\b bold} text.\\par\n"
         "}";
-  pp::VarArrayBuffer array_buffer(rtf_string.size());
+  pp::VarArrayBuffer array_buffer(static_cast<uint32_t>(rtf_string.size()));
   char* bytes = static_cast<char*>(array_buffer.Map());
   std::copy(rtf_string.data(), rtf_string.data() + rtf_string.size(), bytes);
   std::vector<uint32_t> formats_vector(1, PP_FLASH_CLIPBOARD_FORMAT_RTF);
@@ -182,7 +182,7 @@ std::string TestFlashClipboard::TestReadWriteRTF() {
 
 std::string TestFlashClipboard::TestReadWriteCustomData() {
   std::string custom_data = "custom_data";
-  pp::VarArrayBuffer array_buffer(custom_data.size());
+  pp::VarArrayBuffer array_buffer(static_cast<uint32_t>(custom_data.size()));
   char* bytes = static_cast<char*>(array_buffer.Map());
   std::copy(custom_data.begin(), custom_data.end(), bytes);
   uint32_t format_id =
@@ -311,7 +311,7 @@ std::string TestFlashClipboard::TestGetSequenceNumber() {
 
   // Test the sequence number changes after writing some custom data.
   std::string custom_data = "custom_data";
-  pp::VarArrayBuffer array_buffer(custom_data.size());
+  pp::VarArrayBuffer array_buffer(static_cast<uint32_t>(custom_data.size()));
   char* bytes = static_cast<char*>(array_buffer.Map());
   std::copy(custom_data.begin(), custom_data.end(), bytes);
   uint32_t format_id =
diff --git a/ppapi/tests/test_flash_file.cc b/ppapi/tests/test_flash_file.cc
index 8e8db30..b252940 100644
--- a/ppapi/tests/test_flash_file.cc
+++ b/ppapi/tests/test_flash_file.cc
@@ -36,7 +36,8 @@ void CloseFileHandle(PP_FileHandle file_handle) {
 bool WriteFile(PP_FileHandle file_handle, const std::string& contents) {
 #if defined(PPAPI_OS_WIN)
   DWORD bytes_written = 0;
-  BOOL result = ::WriteFile(file_handle, contents.c_str(), contents.size(),
+  BOOL result = ::WriteFile(file_handle, contents.c_str(),
+                            static_cast<DWORD>(contents.size()),
                             &bytes_written, NULL);
   return result && bytes_written == static_cast<DWORD>(contents.size());
 #else
diff --git a/ppapi/tests/test_host_resolver.cc b/ppapi/tests/test_host_resolver.cc
index 2bb5012..27ecae1 100644
--- a/ppapi/tests/test_host_resolver.cc
+++ b/ppapi/tests/test_host_resolver.cc
@@ -85,10 +85,12 @@ std::string TestHostResolver::CheckHTTPResponse(pp::TCPSocket* socket,
                                                 const std::string& response) {
   int32_t rv = 0;
   ASSERT_SUBTEST_SUCCESS(
-      SyncWrite(socket, request.c_str(), request.size(), &rv));
+      SyncWrite(socket, request.c_str(), static_cast<int32_t>(request.size()),
+                &rv));
   std::vector<char> response_buffer(response.size());
   ASSERT_SUBTEST_SUCCESS(
-      SyncRead(socket, &response_buffer[0], response.size(), &rv));
+      SyncRead(socket, &response_buffer[0],
+               static_cast<int32_t>(response.size()), &rv));
   std::string actual_response(&response_buffer[0], rv);
   if (response != actual_response) {
     return "CheckHTTPResponse failed, expected: " + response +
@@ -121,7 +123,7 @@ std::string TestHostResolver::ParameterizedTestResolve(
 
   pp::NetAddress address;
   for (size_t i = 0; i < size; ++i) {
-    address = host_resolver.GetNetAddress(i);
+    address = host_resolver.GetNetAddress(static_cast<uint32_t>(i));
     ASSERT_NE(0, address.pp_resource());
 
     pp::TCPSocket socket(instance_);
@@ -132,7 +134,7 @@ std::string TestHostResolver::ParameterizedTestResolve(
     socket.Close();
   }
 
-  address = host_resolver.GetNetAddress(size);
+  address = host_resolver.GetNetAddress(static_cast<uint32_t>(size));
   ASSERT_EQ(0, address.pp_resource());
   pp::Var canonical_name = host_resolver.GetCanonicalName();
   ASSERT_TRUE(canonical_name.is_string());
diff --git a/ppapi/tests/test_host_resolver_private.cc b/ppapi/tests/test_host_resolver_private.cc
index 88429ed..e13cb99 100644
--- a/ppapi/tests/test_host_resolver_private.cc
+++ b/ppapi/tests/test_host_resolver_private.cc
@@ -100,10 +100,12 @@ std::string TestHostResolverPrivate::CheckHTTPResponse(
     const std::string& response) {
   int32_t rv = 0;
   ASSERT_SUBTEST_SUCCESS(
-      SyncWrite(socket, request.c_str(), request.size(), &rv));
+      SyncWrite(socket, request.c_str(), static_cast<int32_t>(request.size()),
+                &rv));
   std::vector<char> response_buffer(response.size());
   ASSERT_SUBTEST_SUCCESS(
-      SyncRead(socket, &response_buffer[0], response.size(), &rv));
+      SyncRead(socket, &response_buffer[0],
+               static_cast<int32_t>(response.size()), &rv));
   std::string actual_response(&response_buffer[0], rv);
   if (response != actual_response) {
     return "CheckHTTPResponse failed, expected: " + response +
@@ -144,7 +146,8 @@ std::string TestHostResolverPrivate::ParametrizedTestResolve(
 
   PP_NetAddress_Private address;
   for (size_t i = 0; i < size; ++i) {
-    ASSERT_TRUE(host_resolver.GetNetAddress(i, &address));
+    ASSERT_TRUE(host_resolver.GetNetAddress(
+        static_cast<uint32_t>(i), &address));
 
     pp::TCPSocketPrivate socket(instance_);
     ASSERT_SUBTEST_SUCCESS(SyncConnect(&socket, address));
@@ -154,7 +157,8 @@ std::string TestHostResolverPrivate::ParametrizedTestResolve(
     socket.Disconnect();
   }
 
-  ASSERT_FALSE(host_resolver.GetNetAddress(size, &address));
+  ASSERT_FALSE(host_resolver.GetNetAddress(
+      static_cast<uint32_t>(size), &address));
   pp::Var canonical_name = host_resolver.GetCanonicalName();
   ASSERT_TRUE(canonical_name.is_string());
   pp::TCPSocketPrivate socket(instance_);
diff --git a/ppapi/tests/test_memory.cc b/ppapi/tests/test_memory.cc
index 9073227..d4db7c2 100644
--- a/ppapi/tests/test_memory.cc
+++ b/ppapi/tests/test_memory.cc
@@ -30,7 +30,7 @@ void TestMemory::RunTests(const std::string& filter) {
 
 std::string TestMemory::TestMemAlloc() {
   char* buffer = static_cast<char*>(
-      memory_dev_interface_->MemAlloc(kTestBufferSize));
+      memory_dev_interface_->MemAlloc(static_cast<uint32_t>(kTestBufferSize)));
   // Touch a couple of locations.  Failure will crash the test.
   buffer[0] = '1';
   buffer[kTestBufferSize - 1] = '1';
diff --git a/ppapi/tests/test_network_monitor.cc b/ppapi/tests/test_network_monitor.cc
index 2d46f90..dcb712c 100644
--- a/ppapi/tests/test_network_monitor.cc
+++ b/ppapi/tests/test_network_monitor.cc
@@ -64,7 +64,7 @@ std::string TestNetworkMonitor::VerifyNetworkList(
   for (size_t iface = 0; iface < count; ++iface) {
     // Verify that the first interface has at least one address.
     std::vector<pp::NetAddress> addresses;
-    network_list.GetIpAddresses(iface, &addresses);
+    network_list.GetIpAddresses(static_cast<uint32_t>(iface), &addresses);
     ASSERT_TRUE(addresses.size() >= 1U);
     // Verify that the addresses are valid.
     for (size_t i = 0; i < addresses.size(); ++i) {
@@ -115,14 +115,17 @@ std::string TestNetworkMonitor::VerifyNetworkList(
     }
 
     // Verify that each interface has a unique name and a display name.
-    ASSERT_FALSE(network_list.GetName(iface).empty());
-    ASSERT_FALSE(network_list.GetDisplayName(iface).empty());
+    ASSERT_FALSE(network_list.GetName(static_cast<uint32_t>(iface)).empty());
+    ASSERT_FALSE(network_list.GetDisplayName(
+        static_cast<uint32_t>(iface)).empty());
 
-    PP_NetworkList_Type type = network_list.GetType(iface);
+    PP_NetworkList_Type type =
+        network_list.GetType(static_cast<uint32_t>(iface));
     ASSERT_TRUE(type >= PP_NETWORKLIST_TYPE_UNKNOWN);
     ASSERT_TRUE(type <= PP_NETWORKLIST_TYPE_CELLULAR);
 
-    PP_NetworkList_State state = network_list.GetState(iface);
+    PP_NetworkList_State state =
+        network_list.GetState(static_cast<uint32_t>(iface));
     ASSERT_TRUE(state >= PP_NETWORKLIST_STATE_DOWN);
     ASSERT_TRUE(state <= PP_NETWORKLIST_STATE_UP);
   }
diff --git a/ppapi/tests/test_post_message.cc b/ppapi/tests/test_post_message.cc
index 8e7be05..da560cf 100644
--- a/ppapi/tests/test_post_message.cc
+++ b/ppapi/tests/test_post_message.cc
@@ -294,7 +294,7 @@ int TestPostMessage::WaitForMessages() {
   // Now that the FINISHED_WAITING_MESSAGE has been echoed back to us, we know
   // that all pending messages have been slurped up. Return the number we
   // received (which may be zero).
-  return message_data_.size() - message_size_before;
+  return static_cast<int>(message_data_.size() - message_size_before);
 }
 
 std::string TestPostMessage::CheckMessageProperties(
@@ -594,7 +594,7 @@ std::string TestPostMessage::TestSendingResource() {
 
   std::string file_path("/");
   file_path += kTestFilename;
-  int content_length = strlen(kTestString);
+  int content_length = static_cast<int>(strlen(kTestString));
 
   // Create a file in the HTML5 temporary file system, in the Pepper plugin.
   TestCompletionCallback callback(instance_->pp_instance(), callback_type());
diff --git a/ppapi/tests/test_tcp_server_socket_private.cc b/ppapi/tests/test_tcp_server_socket_private.cc
index 2465d51..64b5402 100644
--- a/ppapi/tests/test_tcp_server_socket_private.cc
+++ b/ppapi/tests/test_tcp_server_socket_private.cc
@@ -77,7 +77,8 @@ std::string TestTCPServerSocketPrivate::SyncRead(TCPSocketPrivate* socket,
   while (num_bytes > 0) {
     TestCompletionCallback callback(instance_->pp_instance(), callback_type());
     callback.WaitForResult(
-        socket->Read(buffer, num_bytes, callback.GetCallback()));
+        socket->Read(buffer, static_cast<int32_t>(num_bytes),
+                     callback.GetCallback()));
     CHECK_CALLBACK_BEHAVIOR(callback);
     ASSERT_TRUE(callback.result() >= 0);
     buffer += callback.result();
@@ -92,7 +93,8 @@ std::string TestTCPServerSocketPrivate::SyncWrite(TCPSocketPrivate* socket,
   while (num_bytes > 0) {
     TestCompletionCallback callback(instance_->pp_instance(), callback_type());
     callback.WaitForResult(
-        socket->Write(buffer, num_bytes, callback.GetCallback()));
+        socket->Write(buffer, static_cast<int32_t>(num_bytes),
+                      callback.GetCallback()));
     CHECK_CALLBACK_BEHAVIOR(callback);
     ASSERT_TRUE(callback.result() >= 0);
     buffer += callback.result();
@@ -236,7 +238,7 @@ std::string TestTCPServerSocketPrivate::TestBacklog() {
   }
 
   for (size_t i = 0; i < kBacklog; ++i) {
-    const char byte = 'a' + i;
+    const char byte = static_cast<char>('a' + i);
     ASSERT_SUBTEST_SUCCESS(SyncWrite(client_sockets[i], &byte, sizeof(byte)));
   }
 
diff --git a/ppapi/tests/test_tcp_socket.cc b/ppapi/tests/test_tcp_socket.cc
index a3164de..877b469 100644
--- a/ppapi/tests/test_tcp_socket.cc
+++ b/ppapi/tests/test_tcp_socket.cc
@@ -285,7 +285,7 @@ std::string TestTCPSocket::TestBacklog() {
   }
 
   for (size_t i = 0; i < kBacklog; ++i) {
-    const char byte = 'a' + i;
+    const char byte = static_cast<char>('a' + i);
     ASSERT_SUBTEST_SUCCESS(WriteToSocket(client_sockets[i],
                                          std::string(1, byte)));
   }
@@ -384,7 +384,8 @@ std::string TestTCPSocket::ReadFromSocket(pp::TCPSocket* socket,
   while (num_bytes > 0) {
     TestCompletionCallback callback(instance_->pp_instance(), callback_type());
     callback.WaitForResult(
-        socket->Read(buffer, num_bytes, callback.GetCallback()));
+        socket->Read(buffer, static_cast<int32_t>(num_bytes),
+        callback.GetCallback()));
     CHECK_CALLBACK_BEHAVIOR(callback);
     ASSERT_GT(callback.result(), 0);
     buffer += callback.result();
@@ -401,7 +402,9 @@ std::string TestTCPSocket::WriteToSocket(pp::TCPSocket* socket,
   while (written < s.size()) {
     TestCompletionCallback cb(instance_->pp_instance(), callback_type());
     cb.WaitForResult(
-        socket->Write(buffer + written, s.size() - written, cb.GetCallback()));
+        socket->Write(buffer + written,
+                      static_cast<int32_t>(s.size() - written),
+                      cb.GetCallback()));
     CHECK_CALLBACK_BEHAVIOR(cb);
     ASSERT_GT(cb.result(), 0);
     written += cb.result();
@@ -418,7 +421,8 @@ std::string TestTCPSocket::WriteToSocket_1_0(
   while (written < s.size()) {
     TestCompletionCallback cb(instance_->pp_instance(), callback_type());
     cb.WaitForResult(socket_interface_1_0_->Write(
-        socket, buffer + written, s.size() - written,
+        socket, buffer + written,
+        static_cast<int32_t>(s.size() - written),
         cb.GetCallback().pp_completion_callback()));
     CHECK_CALLBACK_BEHAVIOR(cb);
     ASSERT_GT(cb.result(), 0);
diff --git a/ppapi/tests/test_tcp_socket_private.cc b/ppapi/tests/test_tcp_socket_private.cc
index d3efbe3..0d43a76 100644
--- a/ppapi/tests/test_tcp_socket_private.cc
+++ b/ppapi/tests/test_tcp_socket_private.cc
@@ -246,7 +246,8 @@ int32_t TestTCPSocketPrivate::WriteStringToSocket(pp::TCPSocketPrivate* socket,
   size_t written = 0;
   while (written < s.size()) {
     TestCompletionCallback cb(instance_->pp_instance(), callback_type());
-    int32_t rv = socket->Write(buffer + written, s.size() - written,
+    int32_t rv = socket->Write(buffer + written,
+                               static_cast<int32_t>(s.size() - written),
                                cb.GetCallback());
     if (callback_type() == PP_REQUIRED && rv != PP_OK_COMPLETIONPENDING)
       return PP_ERROR_FAILED;
diff --git a/ppapi/tests/test_udp_socket.cc b/ppapi/tests/test_udp_socket.cc
index 2b05682..89ea036 100644
--- a/ppapi/tests/test_udp_socket.cc
+++ b/ppapi/tests/test_udp_socket.cc
@@ -156,7 +156,8 @@ std::string TestUDPSocket::ReadSocket(pp::UDPSocket* socket,
   TestCompletionCallbackWithOutput<pp::NetAddress> callback(
       instance_->pp_instance(), callback_type());
   callback.WaitForResult(
-      socket->RecvFrom(&buffer[0], size, callback.GetCallback()));
+      socket->RecvFrom(&buffer[0], static_cast<int32_t>(size),
+      callback.GetCallback()));
   CHECK_CALLBACK_BEHAVIOR(callback);
   ASSERT_FALSE(callback.result() < 0);
   ASSERT_EQ(size, static_cast<size_t>(callback.result()));
@@ -171,7 +172,8 @@ std::string TestUDPSocket::PassMessage(pp::UDPSocket* target,
                                        const std::string& message,
                                        pp::NetAddress* recvfrom_address) {
   TestCompletionCallback callback(instance_->pp_instance(), callback_type());
-  int32_t rv = source->SendTo(message.c_str(), message.size(),
+  int32_t rv = source->SendTo(message.c_str(),
+                              static_cast<int32_t>(message.size()),
                               target_address,
                               callback.GetCallback());
   std::string str;
@@ -341,7 +343,7 @@ std::string TestUDPSocket::TestParallelSend() {
         new TestCompletionCallback(instance_->pp_instance(), callback_type());
     sendto_results[i] =
         client_socket.SendTo(message.c_str(),
-                             message.size(),
+                             static_cast<int32_t>(message.size()),
                              server_address,
                              sendto_callbacks[i]->GetCallback());
 
@@ -356,7 +358,7 @@ std::string TestUDPSocket::TestParallelSend() {
       // Try to send the message again.
       sendto_results[i] =
           client_socket.SendTo(message.c_str(),
-                               message.size(),
+                               static_cast<int32_t>(message.size()),
                                server_address,
                                sendto_callbacks[i]->GetCallback());
       ASSERT_NE(PP_ERROR_INPROGRESS, sendto_results[i]);
diff --git a/ppapi/tests/test_udp_socket_private.cc b/ppapi/tests/test_udp_socket_private.cc
index ae1b978..74dd8ba 100644
--- a/ppapi/tests/test_udp_socket_private.cc
+++ b/ppapi/tests/test_udp_socket_private.cc
@@ -138,7 +138,8 @@ std::string TestUDPSocketPrivate::ReadSocket(pp::UDPSocketPrivate* socket,
   std::vector<char> buffer(size);
   TestCompletionCallback callback(instance_->pp_instance(), callback_type());
   callback.WaitForResult(
-      socket->RecvFrom(&buffer[0], size, callback.GetCallback()));
+      socket->RecvFrom(&buffer[0], static_cast<int32_t>(size),
+      callback.GetCallback()));
   CHECK_CALLBACK_BEHAVIOR(callback);
   ASSERT_FALSE(callback.result() < 0);
   ASSERT_EQ(size, static_cast<size_t>(callback.result()));
@@ -151,7 +152,8 @@ std::string TestUDPSocketPrivate::PassMessage(pp::UDPSocketPrivate* target,
                                               PP_NetAddress_Private* address,
                                               const std::string& message) {
   TestCompletionCallback callback(instance_->pp_instance(), callback_type());
-  int32_t rv = source->SendTo(message.c_str(), message.size(), address,
+  int32_t rv = source->SendTo(message.c_str(),
+                              static_cast<int32_t>(message.size()), address,
                               callback.GetCallback());
   std::string str;
   ASSERT_SUBTEST_SUCCESS(ReadSocket(target, address, message.size(), &str));
diff --git a/ppapi/tests/test_url_loader.cc b/ppapi/tests/test_url_loader.cc
index 0d78efa..d3a210e 100644
--- a/ppapi/tests/test_url_loader.cc
+++ b/ppapi/tests/test_url_loader.cc
@@ -37,7 +37,7 @@ int32_t WriteEntireBuffer(PP_Instance instance,
   TestCompletionCallback callback(instance, callback_type);
   int32_t write_offset = offset;
   const char* buf = data.c_str();
-  int32_t size = data.size();
+  int32_t size = static_cast<int32_t>(data.size());
 
   while (write_offset < offset + size) {
     callback.WaitForResult(file_io->Write(write_offset,
@@ -343,7 +343,8 @@ std::string TestURLLoader::TestBasicPOST() {
   request.SetURL("/echo");
   request.SetMethod("POST");
   std::string postdata("postdata");
-  request.AppendDataToBody(postdata.data(), postdata.length());
+  request.AppendDataToBody(postdata.data(),
+                           static_cast<uint32_t>(postdata.length()));
   return LoadAndCompareBody(request, postdata);
 }
 
@@ -394,9 +395,11 @@ std::string TestURLLoader::TestCompoundBodyPOST() {
   request.SetURL("/echo");
   request.SetMethod("POST");
   std::string postdata1("post");
-  request.AppendDataToBody(postdata1.data(), postdata1.length());
+  request.AppendDataToBody(postdata1.data(),
+                           static_cast<uint32_t>(postdata1.length()));
   std::string postdata2("data");
-  request.AppendDataToBody(postdata2.data(), postdata2.length());
+  request.AppendDataToBody(postdata2.data(),
+                           static_cast<uint32_t>(postdata2.length()));
   return LoadAndCompareBody(request, postdata1 + postdata2);
 }
 
@@ -416,7 +419,8 @@ std::string TestURLLoader::TestBinaryDataPOST() {
       "\x00\x01\x02\x03\x04\x05postdata\xfa\xfb\xfc\xfd\xfe\xff";
   std::string postdata(postdata_chars,
                        sizeof(postdata_chars) / sizeof(postdata_chars[0]));
-  request.AppendDataToBody(postdata.data(), postdata.length());
+  request.AppendDataToBody(postdata.data(),
+                           static_cast<uint32_t>(postdata.length()));
   return LoadAndCompareBody(request, postdata);
 }
 
@@ -433,7 +437,8 @@ std::string TestURLLoader::TestFailsBogusContentLength() {
   request.SetMethod("POST");
   request.SetHeaders("Content-Length: 400");
   std::string postdata("postdata");
-  request.AppendDataToBody(postdata.data(), postdata.length());
+  request.AppendDataToBody(postdata.data(),
+                           static_cast<uint32_t>(postdata.length()));
 
   int32_t rv;
   rv = OpenUntrusted(request);
diff --git a/ppapi/tests/test_url_request.cc b/ppapi/tests/test_url_request.cc
index 22b0629..7c9847b 100644
--- a/ppapi/tests/test_url_request.cc
+++ b/ppapi/tests/test_url_request.cc
@@ -77,7 +77,7 @@ void TestURLRequest::RunTests(const std::string& filter) {
 }
 
 PP_Var TestURLRequest::PP_MakeString(const char* s) {
-  return ppb_var_interface_->VarFromUtf8(s, strlen(s));
+  return ppb_var_interface_->VarFromUtf8(s, static_cast<int32_t>(strlen(s)));
 }
 
 // Tests
@@ -357,7 +357,8 @@ std::string TestURLRequest::TestAppendDataToBody() {
 
   // Invalid resource should fail.
   ASSERT_EQ(PP_FALSE, ppb_url_request_interface_->AppendDataToBody(
-      kInvalidResource, postdata.data(), postdata.length()));
+      kInvalidResource, postdata.data(),
+      static_cast<uint32_t>(postdata.length())));
 
   // Append data and POST to echoing web server.
   ASSERT_EQ(PP_TRUE, ppb_url_request_interface_->SetProperty(
@@ -367,7 +368,8 @@ std::string TestURLRequest::TestAppendDataToBody() {
 
   // Append data to body and verify the body is what we expect.
   ASSERT_EQ(PP_TRUE, ppb_url_request_interface_->AppendDataToBody(
-      url_request, postdata.data(), postdata.length()));
+      url_request, postdata.data(),
+      static_cast<uint32_t>(postdata.length())));
   std::string error = LoadAndCompareBody(url_request, postdata);
 
   ppb_var_interface_->Release(post_string_var);
@@ -399,7 +401,7 @@ std::string TestURLRequest::TestAppendFileToBody() {
   std::string append_data = "hello\n";
   callback.WaitForResult(io.Write(0,
                                   append_data.c_str(),
-                                  append_data.size(),
+                                  static_cast<int32_t>(append_data.size()),
                                   callback.GetCallback()));
   CHECK_CALLBACK_BEHAVIOR(callback);
   ASSERT_EQ(static_cast<int32_t>(append_data.size()), callback.result());
diff --git a/ppapi/tests/test_websocket.cc b/ppapi/tests/test_websocket.cc
index e0a54aa..91046f2 100644
--- a/ppapi/tests/test_websocket.cc
+++ b/ppapi/tests/test_websocket.cc
@@ -259,11 +259,13 @@ std::string TestWebSocket::GetFullURL(const char* url) {
 }
 
 PP_Var TestWebSocket::CreateVarString(const std::string& string) {
-  return var_interface_->VarFromUtf8(string.c_str(), string.size());
+  return var_interface_->VarFromUtf8(string.c_str(),
+                                     static_cast<uint32_t>(string.size()));
 }
 
 PP_Var TestWebSocket::CreateVarBinary(const std::vector<uint8_t>& binary) {
-  PP_Var var = arraybuffer_interface_->Create(binary.size());
+  PP_Var var =
+      arraybuffer_interface_->Create(static_cast<uint32_t>(binary.size()));
   uint8_t* var_data = static_cast<uint8_t*>(arraybuffer_interface_->Map(var));
   std::copy(binary.begin(), binary.end(), var_data);
   return var;