Size reduction from moving const char arrays out of header

Change from initial\chrome.dll to out\release\chrome.dll
     .text:   192 bytes change
    .rdata:  -352 bytes change
    .reloc:    28 bytes change
Total change:  -132 bytes

Change from initial\chrome_child.dll to out\release\chrome_child.dll
     .text:  -512 bytes change
    .rdata:  -384 bytes change
    .reloc:  -320 bytes change
Total change: -1216 bytes

This isn't particularly worthwhile for the size savings, but it seems
worthwhile just because const non-integral variable definitions in
header files are not ideal.

BUG=630755
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2523063002
Cr-Commit-Position: refs/heads/master@{#436499}

cc/BUILD.gn

@@ -33,6 +33,7 @@ cc_component("cc") {
     "debug/debug_colors.h",
     "debug/debug_rect_history.cc",
     "debug/debug_rect_history.h",
+    "debug/devtools_instrumentation.cc",
     "debug/devtools_instrumentation.h",
     "debug/frame_rate_counter.cc",
     "debug/frame_rate_counter.h",

cc/debug/devtools_instrumentation.cc

@@ -0,0 +1,34 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "cc/debug/devtools_instrumentation.h"
+
+namespace cc {
+namespace devtools_instrumentation {
+
+namespace internal {
+extern const char kCategory[] = TRACE_DISABLED_BY_DEFAULT("devtools.timeline");
+extern const char kCategoryFrame[] =
+    TRACE_DISABLED_BY_DEFAULT("devtools.timeline.frame");
+extern const char kData[] = "data";
+extern const char kFrameId[] = "frameId";
+extern const char kLayerId[] = "layerId";
+extern const char kLayerTreeId[] = "layerTreeId";
+extern const char kPixelRefId[] = "pixelRefId";
+
+extern const char kImageDecodeTask[] = "ImageDecodeTask";
+extern const char kBeginFrame[] = "BeginFrame";
+extern const char kNeedsBeginFrameChanged[] = "NeedsBeginFrameChanged";
+extern const char kActivateLayerTree[] = "ActivateLayerTree";
+extern const char kRequestMainThreadFrame[] = "RequestMainThreadFrame";
+extern const char kBeginMainThreadFrame[] = "BeginMainThreadFrame";
+extern const char kDrawFrame[] = "DrawFrame";
+extern const char kCompositeLayers[] = "CompositeLayers";
+}  // namespace internal
+
+extern const char kPaintSetup[] = "PaintSetup";
+extern const char kUpdateLayer[] = "UpdateLayer";
+
+}  // namespace devtools_instrumentation
+}  // namespace cc

cc/debug/devtools_instrumentation.h

@@ -18,27 +18,26 @@ namespace cc {
 namespace devtools_instrumentation {
 
 namespace internal {
-const char kCategory[] = TRACE_DISABLED_BY_DEFAULT("devtools.timeline");
-const char kCategoryFrame[] =
-    TRACE_DISABLED_BY_DEFAULT("devtools.timeline.frame");
-const char kData[] = "data";
-const char kFrameId[] = "frameId";
-const char kLayerId[] = "layerId";
-const char kLayerTreeId[] = "layerTreeId";
-const char kPixelRefId[] = "pixelRefId";
-
-const char kImageDecodeTask[] = "ImageDecodeTask";
-const char kBeginFrame[] = "BeginFrame";
-const char kNeedsBeginFrameChanged[] = "NeedsBeginFrameChanged";
-const char kActivateLayerTree[] = "ActivateLayerTree";
-const char kRequestMainThreadFrame[] = "RequestMainThreadFrame";
-const char kBeginMainThreadFrame[] = "BeginMainThreadFrame";
-const char kDrawFrame[] = "DrawFrame";
-const char kCompositeLayers[] = "CompositeLayers";
+extern const char kCategory[];
+extern const char kCategoryFrame[];
+extern const char kData[];
+extern const char kFrameId[];
+extern const char kLayerId[];
+extern const char kLayerTreeId[];
+extern const char kPixelRefId[];
+
+extern const char kImageDecodeTask[];
+extern const char kBeginFrame[];
+extern const char kNeedsBeginFrameChanged[];
+extern const char kActivateLayerTree[];
+extern const char kRequestMainThreadFrame[];
+extern const char kBeginMainThreadFrame[];
+extern const char kDrawFrame[];
+extern const char kCompositeLayers[];
 }  // namespace internal
 
-const char kPaintSetup[] = "PaintSetup";
-const char kUpdateLayer[] = "UpdateLayer";
+extern const char kPaintSetup[];
+extern const char kUpdateLayer[];
 
 class ScopedLayerTask {
  public: