Implements core logic for Pixel Canvas

ui/compositor/compositor_switches.cc

Index: ui/compositor/compositor_switches.cc
diff --git a/ui/compositor/compositor_switches.cc b/ui/compositor/compositor_switches.cc
index 991aba5e0ef1b54462bd01258d1991601f1d7db1..98c781a51127182d23f22be95fc736b61a638b4f 100644
--- a/ui/compositor/compositor_switches.cc
+++ b/ui/compositor/compositor_switches.cc
@@ -32,9 +32,17 @@ const char kUIShowPaintRects[] = "ui-show-paint-rects";
 
 const char kUISlowAnimations[] = "ui-slow-animations";
 
+// If enabled, all draw commands recorded on canvas are done in pixel aligned
+// measurements. This also enables scaling of all elements in views and layers
+// to be done via corner points. See https://goo.gl/Dqig5s
+const char kEnablePixelCanvasRecording[] = "enable-pixel-canvas-recording";
+
 }  // namespace switches
 
 namespace ui {
+namespace {
+bool kEnablePixelCanvasForTesting = false;
+}
 
 bool IsUIZeroCopyEnabled() {
   const base::CommandLine& command_line =
@@ -42,4 +50,15 @@ bool IsUIZeroCopyEnabled() {
   return command_line.HasSwitch(switches::kUIEnableZeroCopy);
 }
 
+bool IsPixelCanvasRecordingEnabled() {
+  static const bool kIsPixelCanvasRecordingEnabled =
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnablePixelCanvasRecording);
+  return kIsPixelCanvasRecordingEnabled || kEnablePixelCanvasForTesting;
+}
+
+void SetPixelCanvasForTesting(bool value) {
+  kEnablePixelCanvasForTesting = value;
+}
+
 }  // namespace ui