Generic version of caching cc switches to avoid searching of switches on each function call

cc/base/switches.cc

 // Copyright (c) 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 "cc/base/switches.h"
 
 #include "base/command_line.h"
 
 namespace cc {
 namespace switches {
@@ skipping 138 matching lines @@
 // Makes pixel tests write their output instead of read it.
 const char kCCRebaselinePixeltests[] = "cc-rebaseline-pixeltests";
 
 // Disable textures using RGBA_4444 layout.
 const char kDisable4444Textures[] = "disable-4444-textures";
 
 // Disable touch hit testing in the compositor.
 const char kDisableCompositorTouchHitTesting[] =
     "disable-compositor-touch-hit-testing";
 
-bool IsLCDTextEnabled() {
-  const CommandLine* command_line = CommandLine::ForCurrentProcess();
-  if (command_line->HasSwitch(cc::switches::kDisableLCDText))
-    return false;
-  else if (command_line->HasSwitch(cc::switches::kEnableLCDText))
-    return true;
+static bool g_has_initialized_switches = false;
+static bool g_impl_side_painting_enabled = false;
+static bool g_map_image_enabled = false;
+static bool g_lcd_text_enabled = false;
+static bool g_gpu_rasterization_enabled = false;
 
+static void InitializeSwitchesIfNeeded() {
+  if (!g_has_initialized_switches) {
+    const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+    // Impl-side painting.
+    if (command_line.HasSwitch(cc::switches::kDisableImplSidePainting)) {
+      g_impl_side_painting_enabled = false;
+    } else if (command_line.HasSwitch(cc::switches::kEnableImplSidePainting)) {
+      g_impl_side_painting_enabled = true;
+    } else {
 #if defined(OS_ANDROID)
-  return false;
+      g_impl_side_painting_enabled = true;
 #else
-  return true;
+      g_impl_side_painting_enabled = false;
 #endif
+    }
+
+    // Map-Image.
+    if (command_line.HasSwitch(cc::switches::kDisableMapImage))
+      g_map_image_enabled = false;
+    else if (command_line.HasSwitch(cc::switches::kEnableMapImage))
+      g_map_image_enabled = true;
+    else
+      g_map_image_enabled = false;
+
+    // LCD-Text.
+    if (command_line.HasSwitch(cc::switches::kDisableLCDText)) {
+      g_lcd_text_enabled = false;
+    } else if (command_line.HasSwitch(cc::switches::kEnableLCDText)) {
+      g_lcd_text_enabled = true;
+    } else {
+#if defined(OS_ANDROID)
+      g_lcd_text_enabled = false;
+#else
+      g_lcd_text_enabled = true;
+#endif
+    }
+
+    // GPU Rasterization.
+    if(command_line.HasSwitch(cc::switches::kEnableGPURasterization)) {
+      g_gpu_rasterization_enabled = true;
+    }
+    g_has_initialized_switches = true;
+  }
 }
 
-namespace {
-bool CheckImplSidePaintingStatus() {
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
-
-  if (command_line.HasSwitch(cc::switches::kDisableImplSidePainting))
-    return false;
-  else if (command_line.HasSwitch(cc::switches::kEnableImplSidePainting))
-    return true;
-
-#if defined(OS_ANDROID)
-  return true;
-#else
-  return false;
-#endif
-}
-}  // namespace
-
 bool IsImplSidePaintingEnabled() {
-  static bool enabled = CheckImplSidePaintingStatus();
-  return enabled;
+  InitializeSwitchesIfNeeded();
+  return g_impl_side_painting_enabled;
 }
 
 bool IsGPURasterizationEnabled() {
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
-  return command_line.HasSwitch(cc::switches::kEnableGPURasterization);
+  InitializeSwitchesIfNeeded();
+  return g_gpu_rasterization_enabled;
 }
 
 bool IsMapImageEnabled() {
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  InitializeSwitchesIfNeeded();
+  return g_map_image_enabled;
+}
 
-  if (command_line.HasSwitch(cc::switches::kDisableMapImage))
-    return false;
-  else if (command_line.HasSwitch(cc::switches::kEnableMapImage))
-    return true;
-
-  return false;
+bool IsLCDTextEnabled() {
+  InitializeSwitchesIfNeeded();
+  return g_lcd_text_enabled;
 }
 
 }  // namespace switches
 }  // namespace cc