Remove dependency of power_save_blocker_android on various content bits

content/browser/wake_lock/wake_lock_service_context.cc

Index: content/browser/wake_lock/wake_lock_service_context.cc
diff --git a/content/browser/wake_lock/wake_lock_service_context.cc b/content/browser/wake_lock/wake_lock_service_context.cc
index 7a706e8582da83c58305cda7e8ceb5517e97495a..3ebf18ac35b301da01f1f380a48fad744b2e0690 100644
--- a/content/browser/wake_lock/wake_lock_service_context.cc
+++ b/content/browser/wake_lock/wake_lock_service_context.cc
@@ -13,6 +13,7 @@
 #include "content/public/browser/power_save_blocker_factory.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/browser/web_contents.h"
 #include "content/public/common/service_registry.h"
 
 namespace content {
@@ -36,6 +37,15 @@ void WakeLockServiceContext::RenderFrameDeleted(
                  render_frame_host->GetRoutingID());
 }
 
+void WakeLockServiceContext::WebContentsDestroyed() {
+#if defined(OS_ANDROID)
+  if (wake_lock_) {
+    static_cast<PowerSaveBlockerImpl*>(wake_lock_.get())
+        ->ClearViewForSleepBlocker();

[ncarter (slow), 2016/06/01 22:01:11]

Now that there are 2 downcasts, consider making wake_lock_ the Impl type, so
that you only have to do the static_cast at CreatePowerSaveBlocker time (where
it's also easier to verify that the cast is safe).

[ncarter (slow), 2016/06/01 22:02:57]

Or don't -- downcasting while assigning a unique_ptr can be a PITA, and it's
probably worse than 2 static_casts.

+  }
+#endif
+}
+
 void WakeLockServiceContext::RequestWakeLock(int render_process_id,
                                              int render_frame_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
@@ -70,7 +80,7 @@ void WakeLockServiceContext::CreateWakeLock() {
   DCHECK(web_contents());
 
   static_cast<PowerSaveBlockerImpl*>(wake_lock_.get())
-      ->InitDisplaySleepBlocker(web_contents());
+      ->InitDisplaySleepBlocker(web_contents()->GetNativeView());
 #endif
 }