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 683101cec9c7be27f3dfb42418bf43128124e880..ff4094662b9126ceadc9492d83e44fd9c6b2948b 100644
--- a/third_party/WebKit/Source/web/WebViewImpl.cpp
+++ b/third_party/WebKit/Source/web/WebViewImpl.cpp
@@ -56,6 +56,7 @@
 #include "core/frame/LocalFrame.h"
 #include "core/frame/PageScaleConstraintsSet.h"
 #include "core/frame/RemoteFrame.h"
+#include "core/frame/ScrollAndScaleEmulator.h"
 #include "core/frame/Settings.h"
 #include "core/frame/SmartClip.h"
 #include "core/frame/TopControls.h"
@@ -3249,6 +3250,23 @@ WebFloatSize WebViewImpl::visualViewportSize() const
     return page()->frameHost().visualViewport().visibleRect().size();
 }
 
+void WebViewImpl::setScrollAndScaleOverride(const IntPoint& framePosition, const DoublePoint& visualViewportPosition, float pageScale)
+{
+    if (!page())
+        return;
+
+    page()->frameHost().setScrollAndScaleOverride(framePosition, visualViewportPosition, pageScale);
+}
+
+void WebViewImpl::clearScrollAndScaleOverride()
+{
+    if (!page())
+        return;
+
+    page()->frameHost().clearScrollAndScaleOverride();
+    resetScrollAndScaleState();
+}
+
 void WebViewImpl::scrollAndRescaleViewports(float scaleFactor,
     const IntPoint& mainFrameOrigin,
     const FloatPoint& visualViewportOrigin)
@@ -3384,7 +3402,13 @@ void WebViewImpl::setIgnoreViewportTagScaleLimits(bool ignore)
 IntSize WebViewImpl::mainFrameSize()
 {
     // The frame size should match the viewport size at minimum scale, since the
-    // viewport must always be contained by the frame.
+    // viewport must always be contained by the frame. As ScrollAndScaleEmulator
+    // may override the minimum scale, it is responsible for this calculation if
+    // it is active.
+    if (page() && page()->frameHost().scrollAndScaleEmulator()) {
+        return page()->frameHost().scrollAndScaleEmulator()->mainFrameSize(m_size);
+    }
+
     FloatSize frameSize(m_size);
     frameSize.scale(1 / minimumPageScaleFactor());
     return expandedIntSize(frameSize);