[DevTools] Use device metrics emulation implemented in content.

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
===================================================================
--- Source/web/WebViewImpl.cpp	(revision 157211)
+++ Source/web/WebViewImpl.cpp	(working copy)
@@ -396,6 +396,7 @@
     , m_contextMenuAllowed(false)
     , m_doingDragAndDrop(false)
     , m_ignoreInputEvents(false)
+    , m_emulatingDeviceScales(false)

[pfeldman, 2013/09/19 12:46:05]

Initialize floats too.

[dgozman, 2013/09/19 13:59:38]

Done.

     , m_suppressNextKeypressEvent(false)
     , m_imeAcceptEvents(true)
     , m_operationsAllowed(WebDragOperationNone)
@@ -2864,8 +2865,7 @@
 
     page()->setDeviceScaleFactor(scaleFactor);
 
-    if (m_layerTreeView)
-        m_layerTreeView->setDeviceScaleFactor(scaleFactor);
+    updateLayerTreeDeviceScaleFactor();
 }
 
 bool WebViewImpl::isFixedLayoutModeEnabled() const
@@ -3703,6 +3703,15 @@
     m_ignoreInputEvents = newValue;
 }
 
+void WebViewImpl::setDeviceEmulationScales(bool enabled, float deviceScaleFactor, float rootLayerScale)
+{
+    m_emulatingDeviceScales = enabled;
+    m_emulatedDeviceScaleFactor = deviceScaleFactor;
+    m_rootLayerScale = rootLayerScale;
+    updateLayerTreeDeviceScaleFactor();
+    updateRootLayerTransform();
+}
+
 void WebViewImpl::addPageOverlay(WebPageOverlay* overlay, int zOrder)
 {
     if (!m_pageOverlays)
@@ -3817,6 +3826,8 @@
 
     setIsAcceleratedCompositingActive(layer);
 
+    updateRootLayerTransform();

[pfeldman, 2013/09/19 12:46:05]

Will this work?:

if (m_emulatingDeviceScales)
    updateRootLayerTransform();

So make sure we don't set identity transform when it is not needed?

[dgozman, 2013/09/19 13:59:38]

What if root layer has transform left from previous emulation? We need to
restore to identity.

+
     if (m_layerTreeView) {
         if (m_rootLayer)
             m_layerTreeView->setRootLayer(*m_rootLayer);
@@ -3924,7 +3935,7 @@
 
             bool visible = page()->visibilityState() == PageVisibilityStateVisible;
             m_layerTreeView->setVisible(visible);
-            m_layerTreeView->setDeviceScaleFactor(page()->deviceScaleFactor());
+            updateLayerTreeDeviceScaleFactor();
             m_layerTreeView->setPageScaleFactorAndLimits(pageScaleFactor(), minimumPageScaleFactor(), maximumPageScaleFactor());
             m_layerTreeView->setBackgroundColor(backgroundColor());
             m_layerTreeView->setHasTransparentBackground(isTransparent());
@@ -4009,6 +4020,27 @@
     m_layerTreeView->setPageScaleFactorAndLimits(pageScaleFactor(), minimumPageScaleFactor(), maximumPageScaleFactor());
 }
 
+void WebViewImpl::updateLayerTreeDeviceScaleFactor()
+{
+    if (!page() || !m_layerTreeView)

[pfeldman, 2013/09/19 12:46:05]

Assert these exist instead.

[dgozman, 2013/09/19 13:59:38]

Done.

+        return;
+
+    float deviceScaleFactor = page()->deviceScaleFactor();
+    if (m_emulatingDeviceScales)

[apavlov, 2013/09/19 12:47:57]

float deviceScaleFactor = m_emulatingDeviceScales ? m_emulatedDeviceScaleFactor
: page()->deviceScaleFactor();

[dgozman, 2013/09/19 13:59:38]

Done.

+        deviceScaleFactor = m_emulatedDeviceScaleFactor;
+    m_layerTreeView->setDeviceScaleFactor(deviceScaleFactor);
+}
+
+void WebViewImpl::updateRootLayerTransform()
+{
+    if (m_rootGraphicsLayer) {
+        WebCore::TransformationMatrix transform;
+        if (m_emulatingDeviceScales)
+            transform = transform.scale(m_rootLayerScale);
+        m_rootGraphicsLayer->setTransform(transform);
+    }
+}
+
 void WebViewImpl::selectAutofillSuggestionAtIndex(unsigned listIndex)
 {
     if (m_autofillPopupClient && listIndex < m_autofillPopupClient->getSuggestionsCount())