[WebView] Create PowerSaveBlocker for fullscreen video.

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 c9d89d655179c3bdb232f6e7866961f08288041e..e0e0f828df209bfd9c8e2493930650bf4287abbd 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -901,6 +901,10 @@ const char kRemoteDebuggingSocketName[]     = "remote-debugging-socket-name";
 // Block ChildProcessMain thread of the renderer's ChildProcessService until a
 // Java debugger is attached.
 const char kRendererWaitForJavaDebugger[] = "renderer-wait-for-java-debugger";
+
+// Enable the PowerSaveBlocker in ContentVideoView. Android only.
+const char kEnableContentVideoViewPowerSaveBlocker[] =
+    "enable-content-video-view-power-save-blocker";
 #endif
 
 // Disable web audio API.