Adds scroll position/scale emulation to DevTools.

third_party/WebKit/Source/web/DevToolsEmulator.cpp

 // Copyright 2015 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 "web/DevToolsEmulator.h"
 
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/Settings.h"
 #include "core/frame/VisualViewport.h"
@@ skipping 221 matching lines @@
 {
     if (!m_deviceMetricsEnabled)
         return;
 
     m_deviceMetricsEnabled = false;
     m_webViewImpl->setBackgroundColorOverride(Color::transparent);
     m_webViewImpl->page()->settings().setDeviceScaleAdjustment(m_embedderDeviceScaleAdjustment);
     disableMobileEmulation();
     m_webViewImpl->setCompositorDeviceScaleFactorOverride(0.f);
     m_webViewImpl->setRootLayerTransform(WebSize(0.f, 0.f), 1.f);
-    m_webViewImpl->setPageScaleFactor(1.f);
+    m_webViewImpl->resetScaleStateImmediately();
     // mainFrameImpl() could be null during cleanup or remote <-> local swap.
     if (m_webViewImpl->mainFrameImpl()) {
+        m_webViewImpl->mainFrameImpl()->frameView()->layout();
         if (Document* document = m_webViewImpl->mainFrameImpl()->frame()->document())
             document->mediaQueryAffectingValueChanged();
     }
 }
 
 bool DevToolsEmulator::resizeIsDeviceSizeChange()
 {
     return m_deviceMetricsEnabled && m_emulateMobileEnabled;
 }
 
@@ skipping 52 matching lines @@
     m_webViewImpl->page()->settings().setAvailablePointerTypes(m_embedderAvailablePointerTypes);
     m_webViewImpl->page()->settings().setPrimaryPointerType(m_embedderPrimaryPointerType);
     m_webViewImpl->page()->settings().setAvailableHoverTypes(m_embedderAvailableHoverTypes);
     m_webViewImpl->page()->settings().setPrimaryHoverType(m_embedderPrimaryHoverType);
     m_webViewImpl->page()->settings().setResizeIsDeviceSizeChange(false);
     m_webViewImpl->setZoomFactorOverride(0);
     m_emulateMobileEnabled = false;
     m_webViewImpl->setDefaultPageScaleLimits(
         m_originalDefaultMinimumPageScaleFactor,
         m_originalDefaultMaximumPageScaleFactor);
-    // mainFrameImpl() could be null during cleanup or remote <-> local swap.
-    if (m_webViewImpl->mainFrameImpl())
-        m_webViewImpl->mainFrameImpl()->frameView()->layout();

[dgozman, 2016/07/21 20:54:08]

This is still needed when we toggle between mobile/desktop emulation (called
from enableDeviceEmulation).

[Eric Seckler, 2016/07/22 14:44:48]

Right, thanks. I think it still makes sense to reset the scale through
resetScaleStateImmediately() in disableDeviceMetrics, which needs a layout. I
think a reasonable solution is to remove the layout() from
enableMobileEmulation, too, and add it to enableDeviceEmulation instead. Done.

 }
 
 void DevToolsEmulator::setTouchEventEmulationEnabled(bool enabled)
 {
     if (m_touchEventEmulationEnabled == enabled)
         return;
     if (!m_touchEventEmulationEnabled) {
         m_originalTouchEnabled = RuntimeEnabledFeatures::touchEnabled();
         m_originalDeviceSupportsMouse = m_webViewImpl->page()->settings().deviceSupportsMouse();
         m_originalDeviceSupportsTouch = m_webViewImpl->page()->settings().deviceSupportsTouch();
@@ skipping 52 matching lines @@
             m_lastPinchAnchorCss.reset();
             m_lastPinchAnchorDip.reset();
         }
         return true;
     }
 
     return false;
 }
 
 } // namespace blink