Adds scroll position/scale emulation to DevTools.

third_party/WebKit/Source/web/WebViewImpl.cpp

Index: third_party/WebKit/Source/web/WebViewImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebViewImpl.cpp b/third_party/WebKit/Source/web/WebViewImpl.cpp
index fad565d27c6eaef57d89c1087056567fb40a7363..61eb90a8860713dfe19f8d7673ddaa8090241ed6 100644
--- a/third_party/WebKit/Source/web/WebViewImpl.cpp
+++ b/third_party/WebKit/Source/web/WebViewImpl.cpp
@@ -419,6 +419,7 @@ WebViewImpl::WebViewImpl(WebViewClient* client)
     , m_enableFakePageScaleAnimationForTesting(false)
     , m_fakePageScaleAnimationPageScaleFactor(0)
     , m_fakePageScaleAnimationUseAnchor(false)
+    , m_scrollOverrideEnabled(false)
     , m_doingDragAndDrop(false)
     , m_ignoreInputEvents(false)
     , m_compositorDeviceScaleFactorOverride(0)
@@ -1818,7 +1819,11 @@ void WebViewImpl::performResize()
     updatePageDefinedViewportConstraints(mainFrameImpl()->frame()->document()->viewportDescription());
     updateMainFrameLayoutSize();
 
-    page()->frameHost().visualViewport().setSize(m_size);
+    if (!(m_scrollOverrideEnabled
+        && (m_scrollOverrideParams.visualViewportSize.width
+            || m_scrollOverrideParams.visualViewportSize.height))) {
+        page()->frameHost().visualViewport().setSize(m_size);
+    }
 
     if (mainFrameImpl()->frameView()) {
         if (!mainFrameImpl()->frameView()->needsLayout())
@@ -3165,6 +3170,18 @@ float WebViewImpl::pageScaleFactor() const
     return page()->frameHost().visualViewport().scale();
 }
 
+WebPoint WebViewImpl::mainFrameOffset() const
+{
+    if (!page() || !mainFrameImpl())
+        return WebPoint();
+
+    FrameView* view = mainFrameImpl()->frameView();
+    if (!view)
+        return WebPoint();
+
+    return view->scrollPosition();
+}
+
 float WebViewImpl::clampPageScaleFactorToLimits(float scaleFactor) const
 {
     return pageScaleConstraintsSet().finalConstraints().clampToConstraints(scaleFactor);
@@ -3188,6 +3205,56 @@ WebFloatSize WebViewImpl::visualViewportSize() const
     return page()->frameHost().visualViewport().visibleRect().size();
 }
 
+void WebViewImpl::setScrollOverride(const WebDeviceEmulationParams& params)
+{
+    if (m_scrollOverrideEnabled && m_scrollOverrideParams == params)
+        return;
+
+    if (!page())
+        return;
+
+    if (!mainFrameImpl())
+        return;
+
+    FrameView * view = mainFrameImpl()->frameView();
+    if (!view)
+        return;
+
+    m_scrollOverrideEnabled = true;
+    m_scrollOverrideParams = params;
+
+    view->setScrollOverride(DoublePoint(
+        m_scrollOverrideParams.scrollPosition.x, m_scrollOverrideParams.scrollPosition.y));
+    page()->frameHost().visualViewport().setScaleAndScrollOverride(
+        m_scrollOverrideParams.visualViewportScale,
+        FloatPoint(
+            m_scrollOverrideParams.visualViewportPosition.x,
+            m_scrollOverrideParams.visualViewportPosition.y));
+}
+
+void WebViewImpl::clearScrollOverride()
+{
+    if (!m_scrollOverrideEnabled)
+        return;
+
+    if (!page())
+        return;
+
+    if (!mainFrameImpl())
+        return;
+
+    FrameView * view = mainFrameImpl()->frameView();
+    if (!view)
+        return;
+
+    m_scrollOverrideEnabled = false;
+
+    view->clearScrollOverride();
+    page()->frameHost().visualViewport().clearScaleAndScrollOverride();
+
+    resetScrollAndScaleState();
+}
+
 void WebViewImpl::scrollAndRescaleViewports(float scaleFactor,
     const IntPoint& mainFrameOrigin,
     const FloatPoint& visualViewportOrigin)
@@ -3848,10 +3915,12 @@ void WebViewImpl::setRootLayerTransform(const WebSize& rootLayerOffset, float ro
 void WebViewImpl::enableDeviceEmulation(const WebDeviceEmulationParams& params)
 {
     m_devToolsEmulator->enableDeviceEmulation(params);
+    setScrollOverride(params);
 }
 
 void WebViewImpl::disableDeviceEmulation()
 {
+    clearScrollOverride();
     m_devToolsEmulator->disableDeviceEmulation();
 }