[SP] Enable Slimming Paint by default in Chromium and Blink.

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index f49c053b38d33e3f5622c1bbc6bab90db6721bd6..6ce78de75055e4c4a5f7046df58781a3a92e9998 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -234,6 +234,10 @@ const char kDisableSetuidSandbox[]          = "disable-setuid-sandbox";
 // Disable shared workers.
 const char kDisableSharedWorkers[]          = "disable-shared-workers";
 
+// Disables slimming paint: http://www.chromium.org/blink/slimming-paint
+// Can be overridden by kEnableSlimmingPaint.
+const char kDisableSlimmingPaint[]           = "disable-slimming-paint";
+
 // Disable smooth scrolling for testing.
 const char kDisableSmoothScrolling[]        = "disable-smooth-scrolling";
 
@@ -411,6 +415,7 @@ const char kEnableSeccompFilterSandbox[] =
 const char kEnableSkiaBenchmarking[]        = "enable-skia-benchmarking";
 
 // Enables slimming paint: http://www.chromium.org/blink/slimming-paint
+// Overrides kDisableSlimmingPaint if both are present.
 const char kEnableSlimmingPaint[]           = "enable-slimming-paint";
 
 // On platforms that support it, enables smooth scroll animation.