Add comments for struct members that were changed from size_t to uin32_t or uint64_t for IPC safety.

Also add a few checked_cast for places where we converted from size_t and we're sure that it's safe.

BUG=581409

Review URL: https://codereview.chromium.org/1684793003

Cr-Commit-Position: refs/heads/master@{#374788}

13 files changed, 35 insertions, 11 deletions

diff --git a/chrome/browser/task_management/sampling/task_group.cc b/chrome/browser/task_management/sampling/task_group.cc
index c8d9bf1..9911136 100644
--- a/chrome/browser/task_management/sampling/task_group.cc
+++ b/chrome/browser/task_management/sampling/task_group.cc
@@ -188,7 +188,7 @@ void TaskGroup::RefreshGpuMemory(
     return;
   }
 
-  gpu_memory_ = static_cast<int64_t>(itr->second.video_memory);
+  gpu_memory_ = itr->second.video_memory;
   gpu_memory_has_duplicates_ = itr->second.has_duplicates;
 }
 
diff --git a/chrome/browser/task_manager/task_manager.cc b/chrome/browser/task_manager/task_manager.cc
index 0ae5fb3..7d87aa7 100644
--- a/chrome/browser/task_manager/task_manager.cc
+++ b/chrome/browser/task_manager/task_manager.cc
@@ -8,6 +8,7 @@
 #include "base/i18n/number_formatting.h"
 #include "base/i18n/rtl.h"
 #include "base/location.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/process/process_metrics.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
@@ -666,7 +667,9 @@ bool TaskManagerModel::GetVideoMemory(int index,
     if (i == video_memory_usage_stats_.process_map.end())
       return false;
     values.is_video_memory_valid = true;
-    values.video_memory = i->second.video_memory;
+    // If this checked_cast asserts, then need to change this code to use
+    // uint64_t instead of size_t.
+    values.video_memory = base::checked_cast<size_t>(i->second.video_memory);
     values.video_memory_has_duplicates = i->second.has_duplicates;
   }
   *video_memory = values.video_memory;
diff --git a/chrome/common/spellcheck_marker.h b/chrome/common/spellcheck_marker.h
index 4305c22..ac278536 100644
--- a/chrome/common/spellcheck_marker.h
+++ b/chrome/common/spellcheck_marker.h
@@ -29,6 +29,9 @@ class SpellCheckMarker {
       : hash(hash), offset(offset) {}
 
   uint32_t hash;
+  // Note: we use uint32_t instead of size_t because this struct is sent over
+  // IPC which could span 32 & 64 bit processes. This is fine since the offset
+  // shouldn't exceed UINT32_MAX even on 64 bit builds.
   uint32_t offset;
 };
 
diff --git a/components/autofill/core/common/form_field_data.h b/components/autofill/core/common/form_field_data.h
index 0317239..a3e923d 100644
--- a/components/autofill/core/common/form_field_data.h
+++ b/components/autofill/core/common/form_field_data.h
@@ -45,6 +45,9 @@ struct FormFieldData {
   base::string16 value;
   std::string form_control_type;
   std::string autocomplete_attribute;
+  // Note: we use uint32_t instead of size_t because this struct is sent over
+  // IPC which could span 32 & 64 bit processes. This is fine since the length
+  // shouldn't exceed UINT32_MAX even on 64 bit builds.
   uint32_t max_length;
   bool is_autofilled;
   bool is_checked;
diff --git a/content/common/gpu/gpu_memory_manager.cc b/content/common/gpu/gpu_memory_manager.cc
index 4b9eb7c..10f769c 100644
--- a/content/common/gpu/gpu_memory_manager.cc
+++ b/content/common/gpu/gpu_memory_manager.cc
@@ -118,7 +118,7 @@ void GpuMemoryManager::SendUmaStatsToBrowser() {
   GPUMemoryUmaStats params;
   params.bytes_allocated_current = GetCurrentUsage();
   params.bytes_allocated_max = bytes_allocated_historical_max_;
-  params.context_group_count = tracking_groups_.size();
+  params.context_group_count = static_cast<uint32_t>(tracking_groups_.size());
   channel_manager_->Send(new GpuHostMsg_GpuMemoryUmaStats(params));
 }
 }  // namespace content
diff --git a/content/common/gpu/gpu_memory_uma_stats.h b/content/common/gpu/gpu_memory_uma_stats.h
index 16c8813..daf91bf 100644
--- a/content/common/gpu/gpu_memory_uma_stats.h
+++ b/content/common/gpu/gpu_memory_uma_stats.h
@@ -11,6 +11,8 @@ namespace content {
 
 // Memory usage statistics send periodically to the browser process to report
 // in UMA histograms if the GPU process crashes.
+// Note: we use uint64_t instead of size_t for byte count because this struct
+// is sent over IPC which could span 32 & 64 bit processes.
 struct GPUMemoryUmaStats {
   GPUMemoryUmaStats()
       : bytes_allocated_current(0),
@@ -19,10 +21,10 @@ struct GPUMemoryUmaStats {
   }
 
   // The number of bytes currently allocated.
-  uint32_t bytes_allocated_current;
+  uint64_t bytes_allocated_current;
 
   // The maximum number of bytes ever allocated at once.
-  uint32_t bytes_allocated_max;
+  uint64_t bytes_allocated_max;
 
   // The number of context groups.
   uint32_t context_group_count;
diff --git a/content/public/common/gpu_memory_stats.h b/content/public/common/gpu_memory_stats.h
index 09bda3f..ed358ab 100644
--- a/content/public/common/gpu_memory_stats.h
+++ b/content/public/common/gpu_memory_stats.h
@@ -17,6 +17,8 @@
 
 namespace content {
 
+// Note: we use uint64_t instead of size_t for byte count because this struct
+// is sent over IPC which could span 32 & 64 bit processes.
 struct CONTENT_EXPORT GPUVideoMemoryUsageStats {
   GPUVideoMemoryUsageStats();
   ~GPUVideoMemoryUsageStats();
@@ -26,7 +28,7 @@ struct CONTENT_EXPORT GPUVideoMemoryUsageStats {
     ~ProcessStats();
 
     // The bytes of GPU resources accessible by this process
-    uint32_t video_memory;
+    uint64_t video_memory;
 
     // Set to true if this process' GPU resource count is inflated because
     // it is counting other processes' resources (e.g, the GPU process has
@@ -39,10 +41,10 @@ struct CONTENT_EXPORT GPUVideoMemoryUsageStats {
   ProcessMap process_map;
 
   // The total amount of GPU memory allocated at the time of the request.
-  uint32_t bytes_allocated;
+  uint64_t bytes_allocated;
 
   // The maximum amount of GPU memory ever allocated at once.
-  uint32_t bytes_allocated_historical_max;
+  uint64_t bytes_allocated_historical_max;
 };
 
 }  // namespace content
diff --git a/extensions/common/stack_frame.h b/extensions/common/stack_frame.h
index b174ffc..a55b8d8 100644
--- a/extensions/common/stack_frame.h
+++ b/extensions/common/stack_frame.h
@@ -29,6 +29,9 @@ struct StackFrame {
 
   bool operator==(const StackFrame& rhs) const;
 
+  // Note: we use uint32_t instead of size_t because this struct is sent over
+  // IPC which could span 32 & 64 bit processes. This is fine since line numbers
+  // and column numbers shouldn't exceed UINT32_MAX even on 64 bit builds.
   uint32_t line_number;
   uint32_t column_number;
   base::string16 source;
diff --git a/media/cast/logging/logging_defines.h b/media/cast/logging/logging_defines.h
index 7d17507..00425be 100644
--- a/media/cast/logging/logging_defines.h
+++ b/media/cast/logging/logging_defines.h
@@ -64,6 +64,8 @@ struct FrameEvent {
   int height;
 
   // Size of encoded frame in bytes. Only set for FRAME_ENCODED event.
+  // Note: we use uint32_t instead of size_t for byte count because this struct
+  // is sent over IPC which could span 32 & 64 bit processes.
   uint32_t size;
 
   // Time of event logged.
diff --git a/media/cast/net/pacing/paced_sender.cc b/media/cast/net/pacing/paced_sender.cc
index 1084901..6de3956 100644
--- a/media/cast/net/pacing/paced_sender.cc
+++ b/media/cast/net/pacing/paced_sender.cc
@@ -8,6 +8,7 @@
 #include "base/bind.h"
 #include "base/debug/dump_without_crashing.h"
 #include "base/message_loop/message_loop.h"
+#include "base/numerics/safe_conversions.h"
 
 namespace media {
 namespace cast {
@@ -354,7 +355,7 @@ void PacedSender::LogPacketEvent(const Packet& packet, CastLoggingEvent type) {
   success &= reader.Skip(2);
   success &= reader.ReadU16(&event.packet_id);
   success &= reader.ReadU16(&event.max_packet_id);
-  event.size = packet.size();
+  event.size = base::checked_cast<uint32_t>(packet.size());
   DCHECK(success);
 }
 
diff --git a/media/cast/receiver/frame_receiver.cc b/media/cast/receiver/frame_receiver.cc
index aa8efb7..7236135 100644
--- a/media/cast/receiver/frame_receiver.cc
+++ b/media/cast/receiver/frame_receiver.cc
@@ -11,6 +11,7 @@
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
+#include "base/numerics/safe_conversions.h"
 #include "media/cast/cast_config.h"
 #include "media/cast/cast_defines.h"
 #include "media/cast/cast_environment.h"
@@ -129,7 +130,7 @@ void FrameReceiver::ProcessParsedPacket(const RtpCastHeader& rtp_header,
   receive_event->frame_id = rtp_header.frame_id;
   receive_event->packet_id = rtp_header.packet_id;
   receive_event->max_packet_id = rtp_header.max_packet_id;
-  receive_event->size = payload_size;
+  receive_event->size = base::checked_cast<uint32_t>(payload_size);
   cast_environment_->logger()->DispatchPacketEvent(std::move(receive_event));
 
   bool duplicate = false;
diff --git a/media/cast/sender/frame_sender.cc b/media/cast/sender/frame_sender.cc
index 535f2eb..8ddfdb7 100644
--- a/media/cast/sender/frame_sender.cc
+++ b/media/cast/sender/frame_sender.cc
@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "base/macros.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/trace_event/trace_event.h"
 #include "media/cast/cast_defines.h"
 #include "media/cast/constants.h"
@@ -239,7 +240,7 @@ void FrameSender::SendEncodedFrame(
   encode_event->media_type = is_audio_ ? AUDIO_EVENT : VIDEO_EVENT;
   encode_event->rtp_timestamp = encoded_frame->rtp_timestamp;
   encode_event->frame_id = frame_id;
-  encode_event->size = encoded_frame->data.size();
+  encode_event->size = base::checked_cast<uint32_t>(encoded_frame->data.size());
   encode_event->key_frame = encoded_frame->dependency == EncodedFrame::KEY;
   encode_event->target_bitrate = requested_bitrate_before_encode;
   encode_event->encoder_cpu_utilization = encoded_frame->deadline_utilization;
diff --git a/ui/gfx/range/range.h b/ui/gfx/range/range.h
index c99ca22..3d9c724 100644
--- a/ui/gfx/range/range.h
+++ b/ui/gfx/range/range.h
@@ -108,6 +108,9 @@ class GFX_EXPORT Range {
   std::string ToString() const;
 
  private:
+  // Note: we use uint32_t instead of size_t because this struct is sent over
+  // IPC which could span 32 & 64 bit processes. This is fine since text spans
+  // shouldn't exceed UINT32_MAX even on 64 bit builds.
   uint32_t start_;
   uint32_t end_;
 };