Adding fading effect for paint rectangles in HUD.

cc/debug/debug_colors.cc

 // Copyright 2012 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 "base/macros.h"
 
 #include "cc/debug/debug_colors.h"
 
 #include "cc/trees/layer_tree_impl.h"
 
@@ skipping 155 matching lines @@
   return SkColorSetRGB(128, 200, 245);
 }
 
 // Evicted tiles get pale red checkerboards.
 SkColor DebugColors::EvictedTileCheckerboardColor() {
   return SkColorSetRGB(255, 200, 200);
 }
 
 // ======= Debug rect colors =======
 
+static SkColor FadedGreen(unsigned initial_value, unsigned step) {
+  unsigned value = step * initial_value / DebugColors::kFadeSteps;

[danakj, 2014/03/06 19:03:21]

DCHECK that step is in [0, kFadeSteps]?

+  return SkColorSetARGB(value, 0, 195, 0);
+}
 // Paint rects in green.
-SkColor DebugColors::PaintRectBorderColor() {
-  return SkColorSetARGB(255, 0, 195, 0);
+SkColor DebugColors::PaintRectBorderColor(unsigned step) {
+  return FadedGreen(255, step);
 }
 int DebugColors::PaintRectBorderWidth() { return 2; }
-SkColor DebugColors::PaintRectFillColor() {
-  return SkColorSetARGB(30, 0, 195, 0);
+SkColor DebugColors::PaintRectFillColor(unsigned step) {
+  return FadedGreen(60, step);
 }
 
 // Property-changed rects in blue.
 SkColor DebugColors::PropertyChangedRectBorderColor() {
   return SkColorSetARGB(255, 0, 0, 255);
 }
 int DebugColors::PropertyChangedRectBorderWidth() { return 2; }
 SkColor DebugColors::PropertyChangedRectFillColor() {
   return SkColorSetARGB(30, 0, 0, 255);
 }
@@ skipping 107 matching lines @@
 SkColor DebugColors::MemoryDisplayTextColor() {
   return SkColorSetARGB(255, 220, 220, 220);
 }
 
 // Paint time display in green (similar to paint times in the WebInspector)
 SkColor DebugColors::PaintTimeDisplayTextAndGraphColor() {
   return SkColorSetRGB(75, 155, 55);
 }
 
 }  // namespace cc