Remember value of IsImplSidePaintingEnabled

Command line arguments are constant at runtime, but the function
cc::switches::IsImplSidePaintingEnabled() does two searches through
the list of arguments every time it's called, and it's called every
time we record a SkPicture.

With this patch, the function remembers the value determined by the
first call and avoids repeating the searches on subsequent calls.

BUG=311248
R=nduca@chromium.org,skyostil@chromium.org

Review URL: https://codereview.chromium.org/43463003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231314 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 8 insertions, 1 deletions

diff --git a/cc/base/switches.cc b/cc/base/switches.cc
index 5dbb296..2eab547 100644
--- a/cc/base/switches.cc
+++ b/cc/base/switches.cc
@@ -162,7 +162,8 @@ bool IsLCDTextEnabled() {
 #endif
 }
 
-bool IsImplSidePaintingEnabled() {
+namespace {
+bool CheckImplSidePaintingStatus() {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
   if (command_line.HasSwitch(cc::switches::kDisableImplSidePainting))
@@ -176,6 +177,12 @@ bool IsImplSidePaintingEnabled() {
   return false;
 #endif
 }
+}  // namespace
+
+bool IsImplSidePaintingEnabled() {
+  static bool enabled = CheckImplSidePaintingStatus();
+  return enabled;
+}
 
 bool IsMapImageEnabled() {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();