webview: Initialize synchronous compositor after first activation.

android_webview/browser/browser_view_renderer.cc

 // Copyright 2014 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 "android_webview/browser/browser_view_renderer.h"
 
 #include "android_webview/browser/browser_view_renderer_client.h"
 #include "android_webview/browser/child_frame.h"
 #include "base/auto_reset.h"
 #include "base/command_line.h"
@@ skipping 432 matching lines @@
   DCHECK(compositor);
   DCHECK(!compositor_);
   compositor_ = compositor;
   UpdateCompositorIsActive();
 }
 
 void BrowserViewRenderer::DidDestroyCompositor(
     content::SynchronousCompositor* compositor) {
   TRACE_EVENT0("android_webview", "BrowserViewRenderer::DidDestroyCompositor");
   DCHECK(compositor_);
+  compositor_->SetIsActive(false);
   compositor_ = NULL;
 }
 
 void BrowserViewRenderer::SetDipScale(float dip_scale) {
   dip_scale_ = dip_scale;
   CHECK_GT(dip_scale_, 0.f);
 }
 
 gfx::Vector2d BrowserViewRenderer::max_scroll_offset() const {
   DCHECK_GT(dip_scale_, 0.f);
@@ skipping 263 matching lines @@
   base::StringAppendF(&str,
                       "overscroll_rounding_error_: %s ",
                       overscroll_rounding_error_.ToString().c_str());
   base::StringAppendF(
       &str, "on_new_picture_enable: %d ", on_new_picture_enable_);
   base::StringAppendF(&str, "clear_view: %d ", clear_view_);
   return str;
 }
 
 }  // namespace android_webview