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);
     // mainFrameImpl() could be null during cleanup or remote <-> local swap.
     if (m_webViewImpl->mainFrameImpl()) {
         if (Document* document = m_webViewImpl->mainFrameImpl()->frame()->document())
             document->mediaQueryAffectingValueChanged();
     }
 }
 
 bool DevToolsEmulator::resizeIsDeviceSizeChange()
 {
     return m_deviceMetricsEnabled && m_emulateMobileEnabled;
@@ skipping 54 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);
+    m_webViewImpl->page()->frameHost().visualViewport().setScale(1.f);

[bokan, 2016/07/04 22:44:09]

I think this does actually belong in disableDeviceEmulation. We need this on
desktop emulation since it can include a touch screen which means the user can
zoom in themselves. We still want to reset the page scale in that case.

You may want to try calling setNeedsReset(true) instead and moving the layout
call below into disableDeviceEmulation as well. That way we'll reset the page
scale to the minimum after the layout.

[Eric Seckler, 2016/07/05 16:46:51]

Done.

     // mainFrameImpl() could be null during cleanup or remote <-> local swap.
     if (m_webViewImpl->mainFrameImpl())
         m_webViewImpl->mainFrameImpl()->frameView()->layout();
 }
 
 void DevToolsEmulator::setTouchEventEmulationEnabled(bool enabled)
 {
     if (m_touchEventEmulationEnabled == enabled)
         return;
     if (!m_touchEventEmulationEnabled) {
@@ skipping 55 matching lines @@
             m_lastPinchAnchorCss.reset();
             m_lastPinchAnchorDip.reset();
         }
         return true;
     }
 
     return false;
 }
 
 } // namespace blink