Resize only the virtual viewport when the OSK triggers a resize.

content/browser/renderer_host/render_process_host_impl.cc

 // Copyright 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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #include <algorithm>
@@ skipping 1365 matching lines @@
     switches::kEnableWebRtcDtls12,
     switches::kEnableWebRtcHWH264Encoding,
     switches::kEnableWebRtcStunOrigin,
     switches::kWebRtcMaxCaptureFramerate,
 #endif
     switches::kEnableLowEndDeviceMode,
     switches::kDisableLowEndDeviceMode,
 #if defined(OS_ANDROID)
     switches::kDisableGestureRequirementForMediaPlayback,
     switches::kDisableWebAudio,
+    switches::kEnableOSKOverscroll,

[jdduke (slow), 2015/10/09 15:17:28]

This flag is unneeded by the renderer process, right?

     switches::kRendererWaitForJavaDebugger,
 #endif
 #if defined(OS_MACOSX)
     // Allow this to be set when invoking the browser and relayed along.
     switches::kEnableSandboxLogging,
 #endif
 #if defined(OS_WIN)
     switches::kDisableDirectWrite,
     switches::kDisableWin32kRendererLockDown,
     switches::kTraceExportEventsToETW,
@@ skipping 1133 matching lines @@
 void RenderProcessHostImpl::GetAudioOutputControllers(
     const GetAudioOutputControllersCallback& callback) const {
   audio_renderer_host()->GetOutputControllers(callback);
 }
 
 BluetoothDispatcherHost* RenderProcessHostImpl::GetBluetoothDispatcherHost() {
   return bluetooth_dispatcher_host_.get();
 }
 
 }  // namespace content