Misc fixes for gn builds with VS 2015

These changes are enough to get gn_all building with VS 2015 in
32-bit gn builds. The changes are mostly to fix warnings about
truncation from size_t to smaller types.

One fix is to avoid illegal #defines, already fixed in the GYP builds.

Warning 4267 is disabled in the main BUILD.gn file because many of the
4244 warnings that VC++ 2013 emits are now emitted as 4267, so we need
to disable 4267 everywhere that 4244 is disabled. Fixing the code is
best done as a separate task.

The code fixes are to avoid truncations, mostly by using more
appropriate types.

BUG=440500

Review URL: https://codereview.chromium.org/1488933002

Cr-Commit-Position: refs/heads/master@{#362858}

6 files changed, 32 insertions, 12 deletions

diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index cce2c5e..b26f033 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -758,6 +758,14 @@ config("default_warnings") {
       "/wd4459",
     ]
 
+    if (visual_studio_version == "2015") {
+      # VC++ 2015 changes 32-bit size_t truncation warnings from 4244 to 4267.
+      # Example: short TruncTest(size_t x) { return x; }
+      # Since we already disable 4244 we need to disable 4267 during migration.
+      # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
+      cflags += [ "/wd4267" ]
+    }
+
     # VS xtree header file needs to be patched or 4702 (unreachable code
     # warning) is reported if _HAS_EXCEPTIONS=0. Disable the warning if xtree is
     # not patched.
diff --git a/google_apis/gcm/base/mcs_util_unittest.cc b/google_apis/gcm/base/mcs_util_unittest.cc
index d51f5a07..34d482d 100644
--- a/google_apis/gcm/base/mcs_util_unittest.cc
+++ b/google_apis/gcm/base/mcs_util_unittest.cc
@@ -31,12 +31,12 @@ TEST(MCSUtilTest, BuildLoginRequest) {
 
 // Test building a protobuf and extracting the tag from a protobuf.
 TEST(MCSUtilTest, ProtobufToTag) {
-  for (size_t i = 0; i < kNumProtoTypes; ++i) {
+  for (uint8 i = 0; i < kNumProtoTypes; ++i) {
     scoped_ptr<google::protobuf::MessageLite> protobuf =
         BuildProtobufFromTag(i);
     if (!protobuf.get())  // Not all tags have protobuf definitions.
       continue;
-    ASSERT_EQ((int)i, GetMCSProtoTag(*protobuf)) << "Type " << i;
+    ASSERT_EQ(i, GetMCSProtoTag(*protobuf)) << "Type " << i;
   }
 }
 
diff --git a/gpu/command_buffer/client/query_tracker.cc b/gpu/command_buffer/client/query_tracker.cc
index ec678a2..f5363f0 100644
--- a/gpu/command_buffer/client/query_tracker.cc
+++ b/gpu/command_buffer/client/query_tracker.cc
@@ -67,7 +67,7 @@ bool QuerySyncManager::Alloc(QuerySyncManager::QueryInfo* info) {
     buckets_.push_back(bucket);
   }
 
-  unsigned short index_in_bucket = 0;
+  size_t index_in_bucket = 0;
   for (size_t i = 0; i < kSyncsPerBucket; i++) {
     if (!bucket->in_use_queries[i]) {
       index_in_bucket = i;
diff --git a/printing/printing_context_win_unittest.cc b/printing/printing_context_win_unittest.cc
index aab83f3..6b2b20f 100644
--- a/printing/printing_context_win_unittest.cc
+++ b/printing/printing_context_win_unittest.cc
@@ -118,13 +118,13 @@ class MockPrintingContextWin : public PrintingContextSytemDialogWin {
     memcpy(reinterpret_cast<uint8*>(dev_names_ptr) + dev_names->wDriverOffset,
            info_2.get()->pDriverName,
            driver_size);
-    dev_names->wDeviceOffset =
-        dev_names->wDriverOffset + driver_size / sizeof(wchar_t);
+    dev_names->wDeviceOffset = base::checked_cast<WORD>(
+        dev_names->wDriverOffset + driver_size / sizeof(wchar_t));
     memcpy(reinterpret_cast<uint8*>(dev_names_ptr) + dev_names->wDeviceOffset,
            info_2.get()->pPrinterName,
            printer_size);
-    dev_names->wOutputOffset =
-        dev_names->wDeviceOffset + printer_size / sizeof(wchar_t);
+    dev_names->wOutputOffset = base::checked_cast<WORD>(
+        dev_names->wDeviceOffset + printer_size / sizeof(wchar_t));
     memcpy(reinterpret_cast<uint8*>(dev_names_ptr) + dev_names->wOutputOffset,
            info_2.get()->pPortName,
            port_size);
diff --git a/third_party/leveldatabase/BUILD.gn b/third_party/leveldatabase/BUILD.gn
index b3080d8..0057c0e 100644
--- a/third_party/leveldatabase/BUILD.gn
+++ b/third_party/leveldatabase/BUILD.gn
@@ -282,6 +282,13 @@ if (!is_android) {
     deps = [
       ":leveldb_testutil",
     ]
+
+    if (is_win) {
+      # db\log_test.cc(486) triggers two warnings:
+      # util\testharness.h(91): warning C4018: '<=': signed/unsigned mismatch
+      # util\testharness.h(89): warning C4018: '>=': signed/unsigned mismatch
+      cflags = [ "/wd4018" ]  # Signed/unsigned mismatch in comparison.
+    }
   }
 
   test("leveldb_skiplist_test") {
diff --git a/third_party/libexif/BUILD.gn b/third_party/libexif/BUILD.gn
index 3f88f1c9..ea9ca90 100644
--- a/third_party/libexif/BUILD.gn
+++ b/third_party/libexif/BUILD.gn
@@ -57,11 +57,16 @@ if (!is_linux || is_chromeos) {
     # TODO(GYP): Additional options for non-Windows platforms.
 
     if (is_win) {
-      defines = [
-        # This seems like a hack, but this is what WebKit Win does.
-        "snprintf=_snprintf",
-        "inline=__inline",
-      ]
+      import("//build/config/win/visual_studio_version.gni")
+
+      if (visual_studio_version == "2013" || visual_studio_version == "2013e") {
+        defines = [
+          # This seems like a hack, but this is what WebKit Win does.
+          # VS 2015 supports these natively so they cannot be #defines.
+          "snprintf=_snprintf",
+          "inline=__inline",
+        ]
+      }
 
       ldflags = [ "/DEF:" + rebase_path("libexif.def") ]