content: Move shader cache factory singleton into a separate file.

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index e76edcb988c27b65f6f760ba79de7313f0591df4..862489ce6103ac4fd45a4622b654e5eca283586c 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -60,7 +60,7 @@
 #include "content/browser/gpu/gpu_data_manager_impl.h"
 #include "content/browser/gpu/gpu_process_host.h"
 #include "content/browser/gpu/gpu_process_host_ui_shim.h"
-#include "content/browser/gpu/shader_disk_cache.h"
+#include "content/browser/gpu/shader_cache_factory.h"
 #include "content/browser/histogram_synchronizer.h"
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 #include "content/browser/loader_delegate_impl.h"
@@ -1342,7 +1342,7 @@ int BrowserMainLoop::BrowserThreadsStarted() {
   // Initialize the GPU shader cache. This needs to be initialized before
   // BrowserGpuChannelHostFactory below, since that depends on an initialized
   // ShaderCacheFactory.
-  ShaderCacheFactory::InitInstance(
+  InitShaderCacheFactorySingleton(
       BrowserThread::GetTaskRunnerForThread(BrowserThread::IO),
       BrowserThread::GetTaskRunnerForThread(BrowserThread::CACHE));