Adds scroll position/scale emulation to DevTools.

third_party/WebKit/Source/web/tests/WebViewTest.cpp

Index: third_party/WebKit/Source/web/tests/WebViewTest.cpp
diff --git a/third_party/WebKit/Source/web/tests/WebViewTest.cpp b/third_party/WebKit/Source/web/tests/WebViewTest.cpp
index a32e4562bcd64f4aa8be19556a92a42d1114d5fa..c9cd57c9d855ed4326d6ba33e047879eb66bebac 100644
--- a/third_party/WebKit/Source/web/tests/WebViewTest.cpp
+++ b/third_party/WebKit/Source/web/tests/WebViewTest.cpp
@@ -40,6 +40,8 @@
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
+#include "core/frame/PageScaleConstraints.h"
+#include "core/frame/PageScaleConstraintsSet.h"
 #include "core/frame/Settings.h"
 #include "core/frame/VisualViewport.h"
 #include "core/html/HTMLDocument.h"
@@ -110,6 +112,27 @@ using blink::testing::runPendingTasks;
 
 namespace blink {
 
+#define EXPECT_POINT_EQ(expected, actual)               \
+    do {                                                \
+        EXPECT_DOUBLE_EQ((expected).x(), (actual).x()); \
+        EXPECT_DOUBLE_EQ((expected).y(), (actual).y()); \
+    } while (false)
+
+#define EXPECT_SIZE_EQ(expected, actual)               \
+    do {                                                 \
+        EXPECT_DOUBLE_EQ((expected).width(), (actual).width());   \
+        EXPECT_DOUBLE_EQ((expected).height(), (actual).height()); \
+    } while (false)
+
+#define EXPECT_SCROLL_AND_SCALE(expectedScrollPosition, expectedVisualPosition, expectedScale, frameView, visualViewport) \
+    do { \
+        EXPECT_POINT_EQ(expectedScrollPosition, frameView->scrollPositionDouble()); \
+        EXPECT_POINT_EQ(expectedScrollPosition, frameView->scrollAnimator().currentPosition()); \
+        EXPECT_POINT_EQ(expectedVisualPosition, visualViewport->scrollPositionDouble()); \
+        EXPECT_POINT_EQ(expectedVisualPosition, visualViewport->scrollAnimator().currentPosition()); \
+        EXPECT_EQ(expectedScale, visualViewport->scale()); \
+    } while (false)
+
 enum HorizontalScrollbarState {
     NoHorizontalScrollbar,
     VisibleHorizontalScrollbar,
@@ -1067,6 +1090,469 @@ TEST_F(WebViewTest, IsSelectionAnchorFirst)
     EXPECT_FALSE(webView->isSelectionAnchorFirst());
 }
 
+TEST_F(WebViewTest, DeviceEmulationOverridesMoveAndZoomViewports)
+{
+    URLTestHelpers::registerMockedURLFromBaseURL(WebString::fromUTF8(m_baseURL.c_str()), WebString::fromUTF8("200-by-300.html"));
+    WebViewImpl* webViewImpl = m_webViewHelper.initializeAndLoad(m_baseURL + "200-by-300.html");
+    webViewImpl->resize(WebSize(100, 150));
+    webViewImpl->resizeVisualViewport(WebSize(50, 75));
+
+    FrameView* frameView = webViewImpl->mainFrameImpl()->frame()->view();
+    VisualViewport* visualViewport = &webViewImpl->page()->frameHost().visualViewport();
+    WebDeviceEmulationParams params;
+
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Scroll position override moves layout viewport.
+    params.scrollPosition = WebPoint(100, 100);
+    params.visualViewportPosition = WebFloatPoint(-1, -1);
+    params.visualViewportScale = 0;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_FALSE(frameView->layoutPending());
+    EXPECT_FALSE(frameView->needsLayout());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 100), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    params.scrollPosition = WebPoint(50, 50);
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Visual viewport scroll position override moves visual viewport.
+    params.scrollPosition = WebPoint(-1, -1);
+    params.visualViewportPosition = WebFloatPoint(50, 50);
+    params.visualViewportScale = 0;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_FALSE(frameView->layoutPending());
+    EXPECT_FALSE(frameView->needsLayout());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(50, 50), 1.0, frameView, visualViewport);
+
+    params.visualViewportPosition = WebFloatPoint(25, 25);
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Page scale override zooms into page.
+    params.scrollPosition = WebPoint(-1, -1);
+    params.visualViewportPosition = WebFloatPoint(-1, -1);
+    params.visualViewportScale = 2;
+    webViewImpl->enableDeviceEmulation(params);
+    // Scale override is enforced via constraints, which require a layout.
+    EXPECT_TRUE(frameView->layoutPending());
+    EXPECT_TRUE(frameView->needsLayout());
+    frameView->layout();

[bokan, 2016/07/11 13:52:10]

I would use webViewImpl->updateAllLifecyclePhases, which is the higher-level way
of doing style/layout/painting, etc. It'll call frameView->layout as part of it.

[Eric Seckler, 2016/07/11 16:37:13]

Done.

+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 2.0, frameView, visualViewport);
+
+    params.visualViewportScale = 1.5;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_TRUE(frameView->layoutPending());
+    EXPECT_TRUE(frameView->needsLayout());
+    frameView->layout();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.5, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);

[bokan, 2016/07/11 13:52:10]

Should we also expect needsLayout/layoutPending here? Since disabling device
emulation changes the page scale?

[Eric Seckler, 2016/07/11 16:37:13]

Theoretically yes, but disableDeviceEmulation() performs a layout already within
the DevToolsEmulator, so the needsLayout() is already taken care of. Added a
comment instead.

+
+    // Combined override of all factors repositions and scales viewports.
+    params.scrollPosition = WebPoint(100, 100);
+    params.visualViewportPosition = WebFloatPoint(50, 50);
+    params.visualViewportScale = 2;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_TRUE(frameView->layoutPending());
+    EXPECT_TRUE(frameView->needsLayout());
+    frameView->layout();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 100), DoublePoint(50, 50), 2.0, frameView, visualViewport);
+
+    params.scrollPosition = WebPoint(50, 50);
+    params.visualViewportPosition = WebFloatPoint(25, 25);
+    params.visualViewportScale = 1.5;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_TRUE(frameView->layoutPending());
+    EXPECT_TRUE(frameView->needsLayout());
+    frameView->layout();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.5, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+}
+
+TEST_F(WebViewTest, DeviceEmulationOverridesFixScaleAndScrollPositions)
+{
+    URLTestHelpers::registerMockedURLFromBaseURL(WebString::fromUTF8(m_baseURL.c_str()), WebString::fromUTF8("200-by-300.html"));
+    WebViewImpl* webViewImpl = m_webViewHelper.initializeAndLoad(m_baseURL + "200-by-300.html");
+    webViewImpl->resize(WebSize(100, 150));
+    webViewImpl->resizeVisualViewport(WebSize(50, 75));
+
+    // We don't want to have to service animations for the test.
+    webViewImpl->settings()->setEnableScrollAnimator(false);
+
+    FrameView* frameView = webViewImpl->mainFrameImpl()->frame()->view();
+    VisualViewport* visualViewport = &webViewImpl->page()->frameHost().visualViewport();
+    ScrollableArea* rootScroller = frameView->getScrollableArea();
+    WebDeviceEmulationParams params;
+
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Empty overrides allow scrolling and zooming.
+    params.scrollPosition = WebPoint(-1, -1);
+    params.visualViewportPosition = WebFloatPoint(-1, -1);
+    params.visualViewportScale = 0;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    frameView->setScrollPosition(DoublePoint(100, 100), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 100), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    visualViewport->setScrollPosition(DoublePoint(50, 50), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 100), DoublePoint(50, 50), 1.0, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(-50, -50)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 100), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(-50, -50)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    webViewImpl->setPageScaleFactor(2.0);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(0, 0), 2.0, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Override of scroll position fixes layout viewport, but not visual one.
+    params.scrollPosition = WebPoint(50, 50);
+    params.visualViewportPosition = WebFloatPoint(-1, -1);
+    params.visualViewportScale = 0;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    frameView->setScrollPosition(DoublePoint(100, 100), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    visualViewport->setScrollPosition(DoublePoint(50, 50), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(50, 50), 1.0, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(-50, -50)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    EXPECT_FALSE(rootScroller->userScroll(ScrollByPixel, FloatSize(-50, -50)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(1000, 1000)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(50, 75), 1.0, frameView, visualViewport);
+    webViewImpl->setPageScaleFactor(2.0);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(50, 75), 2.0, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Override of visual position fixes visual viewport, but not layout one.
+    params.scrollPosition = WebPoint(-1, -1);
+    params.visualViewportPosition = WebFloatPoint(25, 25);
+    params.visualViewportScale = 0;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+
+    frameView->setScrollPosition(DoublePoint(100, 100), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 100), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+    visualViewport->setScrollPosition(DoublePoint(50, 50), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 100), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(-100, -100)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+    EXPECT_FALSE(rootScroller->userScroll(ScrollByPixel, FloatSize(-50, -50)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(1000, 1000)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 150), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+    webViewImpl->setPageScaleFactor(2.0);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 150), DoublePoint(25, 25), 2.0, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Scroll position: override of one coordinate doesn't fix other one.
+    params.scrollPosition = WebPoint(-1, 50);
+    params.visualViewportPosition = WebFloatPoint(-1, -1);
+    params.visualViewportScale = 0;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 50), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    frameView->setScrollPosition(DoublePoint(100, 100), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 50), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(-100, -100)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 50), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    params.scrollPosition = WebPoint(50, -1);
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    frameView->setScrollPosition(DoublePoint(100, 100), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 100), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(-100, -100)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Visual position: override of one coordinate doesn't fix other one.
+    params.scrollPosition = WebPoint(-1, -1);
+    params.visualViewportPosition = WebFloatPoint(-1, 25);
+    params.visualViewportScale = 0;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 25), 1.0, frameView, visualViewport);
+
+    visualViewport->setScrollPosition(DoublePoint(50, 50), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(50, 25), 1.0, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(-50, -50)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 25), 1.0, frameView, visualViewport);
+
+    params.visualViewportPosition = WebFloatPoint(25, -1);
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+    visualViewport->setScrollPosition(DoublePoint(50, 50), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(25, 50), 1.0, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(-50, -50)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(25, 0), 1.0, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Scale change is ignored when scale is overridden, but scrolls work.
+    params.scrollPosition = WebPoint(-1, -1);
+    params.visualViewportPosition = WebFloatPoint(-1, -1);
+    params.visualViewportScale = 1.5;
+    webViewImpl->enableDeviceEmulation(params);
+    frameView->layout();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.5, frameView, visualViewport);
+
+    frameView->setScrollPosition(DoublePoint(100, 100), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 100), DoublePoint(0, 0), 1.5, frameView, visualViewport);
+    visualViewport->setScrollPosition(DoublePoint(50, 50), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 100), DoublePoint(50, 50), 1.5, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(-50, -50)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 100), DoublePoint(0, 0), 1.5, frameView, visualViewport);
+    EXPECT_TRUE(rootScroller->userScroll(ScrollByPixel, FloatSize(-50, -50)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(0, 0), 1.5, frameView, visualViewport);
+    webViewImpl->setPageScaleFactor(2.0);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(0, 0), 1.5, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Scrolling is ignored when both scroll positions are fixed, but not zoom.
+    params.scrollPosition = WebPoint(50, 50);
+    params.visualViewportPosition = WebFloatPoint(25, 25);
+    params.visualViewportScale = 0;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+
+    frameView->setScrollPosition(DoublePoint(100, 100), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+    visualViewport->setScrollPosition(DoublePoint(50, 50), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+    EXPECT_FALSE(rootScroller->userScroll(ScrollByPixel, FloatSize(-50, -50)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+    EXPECT_FALSE(rootScroller->userScroll(ScrollByPixel, FloatSize(1000, 1000)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.0, frameView, visualViewport);
+    webViewImpl->setPageScaleFactor(2.0);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 2.0, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Both scrolling and scale changes are ignored when they are all fixed.
+    params.scrollPosition = WebPoint(50, 50);
+    params.visualViewportPosition = WebFloatPoint(25, 25);
+    params.visualViewportScale = 1.5;
+    webViewImpl->enableDeviceEmulation(params);
+    frameView->layout();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.5, frameView, visualViewport);
+
+    frameView->setScrollPosition(DoublePoint(100, 100), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.5, frameView, visualViewport);
+    visualViewport->setScrollPosition(DoublePoint(50, 50), ProgrammaticScroll, ScrollBehaviorInstant);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.5, frameView, visualViewport);
+    EXPECT_FALSE(rootScroller->userScroll(ScrollByPixel, FloatSize(-50, -50)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.5, frameView, visualViewport);
+    EXPECT_FALSE(rootScroller->userScroll(ScrollByPixel, FloatSize(1000, 1000)).didScroll());
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.5, frameView, visualViewport);
+    webViewImpl->setPageScaleFactor(2.0);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(50, 50), DoublePoint(25, 25), 1.5, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+}
+
+TEST_F(WebViewTest, DeviceEmulationScrollOverridesAreClamped)
+{
+    URLTestHelpers::registerMockedURLFromBaseURL(WebString::fromUTF8(m_baseURL.c_str()), WebString::fromUTF8("200-by-300.html"));
+    WebViewImpl* webViewImpl = m_webViewHelper.initializeAndLoad(m_baseURL + "200-by-300.html");
+    webViewImpl->resize(WebSize(100, 150));
+    webViewImpl->resizeVisualViewport(WebSize(50, 75));
+
+    FrameView* frameView = webViewImpl->mainFrameImpl()->frame()->view();
+    VisualViewport* visualViewport = &webViewImpl->page()->frameHost().visualViewport();
+    WebDeviceEmulationParams params;
+
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Scroll position override is clamped to maximum.
+    params.scrollPosition = WebPoint(1000, 1000);
+    params.visualViewportPosition = WebFloatPoint(-1, -1);
+    params.visualViewportScale = 0;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(100, 150), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Viewport scroll position override is clamped to maximum.
+    params.scrollPosition = WebPoint(-1, -1);
+    params.visualViewportPosition = WebFloatPoint(1000, 1000);
+    params.visualViewportScale = 0;
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(50, 75), 1.0, frameView, visualViewport);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+}
+
+TEST_F(WebViewTest, DeviceEmulationDisablesAndRestoresThreadedScrolling)
+{
+    URLTestHelpers::registerMockedURLFromBaseURL(WebString::fromUTF8(m_baseURL.c_str()), WebString::fromUTF8("200-by-300.html"));
+    WebViewImpl* webViewImpl = m_webViewHelper.initializeAndLoad(m_baseURL + "200-by-300.html");
+    webViewImpl->resize(WebSize(100, 150));
+    webViewImpl->resizeVisualViewport(WebSize(50, 75));
+
+    FrameView* frameView = webViewImpl->mainFrameImpl()->frame()->view();
+    VisualViewport* visualViewport = &webViewImpl->page()->frameHost().visualViewport();
+    WebDeviceEmulationParams params;
+
+    EXPECT_TRUE(webViewImpl->page()->settings().threadedScrollingEnabled());
+
+    // Setting scroll override disables threaded scrolling and sets main thread
+    // scrolling reasons.
+    params.scrollPosition = WebPoint(0, 0);
+    params.visualViewportPosition = WebFloatPoint(0, 0);
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_FALSE(webViewImpl->page()->settings().threadedScrollingEnabled());
+    webViewImpl->updateAllLifecyclePhases();
+    EXPECT_TRUE(frameView->layerForScrolling()->platformLayer()->shouldScrollOnMainThread());
+    EXPECT_TRUE(visualViewport->layerForScrolling()->platformLayer()->shouldScrollOnMainThread());
+
+    // Clearing override restores original setting.
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_TRUE(webViewImpl->page()->settings().threadedScrollingEnabled());
+    webViewImpl->updateAllLifecyclePhases();
+    EXPECT_FALSE(frameView->layerForScrolling()->platformLayer()->shouldScrollOnMainThread());
+    EXPECT_FALSE(visualViewport->layerForScrolling()->platformLayer()->shouldScrollOnMainThread());
+
+    // Updating scroll override does not override stored default.
+    params.scrollPosition = WebPoint(0, 0);
+    params.visualViewportPosition = WebFloatPoint(0, 0);
+    webViewImpl->enableDeviceEmulation(params);
+    params.scrollPosition = WebPoint(100, 100);
+    webViewImpl->enableDeviceEmulation(params);
+    EXPECT_FALSE(webViewImpl->page()->settings().threadedScrollingEnabled());
+    webViewImpl->updateAllLifecyclePhases();
+    EXPECT_TRUE(frameView->layerForScrolling()->platformLayer()->shouldScrollOnMainThread());
+    EXPECT_TRUE(visualViewport->layerForScrolling()->platformLayer()->shouldScrollOnMainThread());
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_TRUE(webViewImpl->page()->settings().threadedScrollingEnabled());
+    webViewImpl->updateAllLifecyclePhases();
+    EXPECT_FALSE(frameView->layerForScrolling()->platformLayer()->shouldScrollOnMainThread());
+    EXPECT_FALSE(visualViewport->layerForScrolling()->platformLayer()->shouldScrollOnMainThread());
+}
+
+TEST_F(WebViewTest, DeviceEmulationScaleOverrideDoesNotAffectMainFrameSize)
+{
+    URLTestHelpers::registerMockedURLFromBaseURL(WebString::fromUTF8(m_baseURL.c_str()), WebString::fromUTF8("200-by-300.html"));
+    WebViewImpl* webViewImpl = m_webViewHelper.initializeAndLoad(m_baseURL + "200-by-300.html");
+    webViewImpl->resize(WebSize(100, 150));
+    webViewImpl->resizeVisualViewport(WebSize(50, 75));
+
+    FrameView* frameView = webViewImpl->mainFrameImpl()->frame()->view();
+    VisualViewport* visualViewport = &webViewImpl->page()->frameHost().visualViewport();
+    WebDeviceEmulationParams params;
+
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+
+    // Main frame size is normally calculated by dividing by minimum scale.
+    // Since scale override changes minimum scale, we need to ensure that the
+    // calculated main frame size does not change.
+    IntSize expectedSize = webViewImpl->mainFrameSize();
+    params.visualViewportScale = 2.0;
+    webViewImpl->enableDeviceEmulation(params);
+    frameView->layout();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 2.0, frameView, visualViewport);
+    EXPECT_SIZE_EQ(expectedSize, webViewImpl->mainFrameSize());
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    EXPECT_SIZE_EQ(expectedSize, webViewImpl->mainFrameSize());
+
+    // Same behavior for non-default minimum scale.
+    webViewImpl->setDefaultPageScaleLimits(0.25, 5.0);
+    frameView->layout();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 0.25, frameView, visualViewport);
+    expectedSize = webViewImpl->mainFrameSize();
+    params.visualViewportScale = 2.0;
+    webViewImpl->enableDeviceEmulation(params);
+    frameView->layout();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 2.0, frameView, visualViewport);
+    EXPECT_SIZE_EQ(expectedSize, webViewImpl->mainFrameSize());

[bokan, 2016/07/11 13:52:10]

Maybe add a resize while the override is in place to make sure the mainFrameSize
resizes as expected?

[Eric Seckler, 2016/07/11 16:37:13]

Done.

+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 0.25, frameView, visualViewport);
+    EXPECT_SIZE_EQ(expectedSize, webViewImpl->mainFrameSize());
+}
+
+TEST_F(WebViewTest, DeviceEmulationScaleOverrideSetsAndRestoresPageScaleConstraints)
+{
+    URLTestHelpers::registerMockedURLFromBaseURL(WebString::fromUTF8(m_baseURL.c_str()), WebString::fromUTF8("200-by-300.html"));
+    WebViewImpl* webViewImpl = m_webViewHelper.initializeAndLoad(m_baseURL + "200-by-300.html");
+    webViewImpl->resize(WebSize(100, 150));
+    webViewImpl->resizeVisualViewport(WebSize(50, 75));
+
+    FrameView* frameView = webViewImpl->mainFrameImpl()->frame()->view();
+    VisualViewport* visualViewport = &webViewImpl->page()->frameHost().visualViewport();
+    WebDeviceEmulationParams params;
+
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    PageScaleConstraints originalConstraints(1.0, 0.5, 2.0);
+    webViewImpl->page()->frameHost().setUserAgentPageScaleConstraints(originalConstraints);
+    frameView->layout();
+    EXPECT_EQ(originalConstraints.initialScale, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().initialScale);
+    EXPECT_EQ(originalConstraints.minimumScale, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().minimumScale);
+    EXPECT_EQ(originalConstraints.maximumScale, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().maximumScale);
+
+    // Setting and clearing scale override restores original user-agent page
+    // scale constraints setting.
+    params.visualViewportScale = 3.0;
+    webViewImpl->enableDeviceEmulation(params);
+    frameView->layout();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 3.0, frameView, visualViewport);
+    EXPECT_EQ(3.0, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().initialScale);
+    EXPECT_EQ(3.0, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().minimumScale);
+    EXPECT_EQ(3.0, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().maximumScale);
+
+    params.visualViewportScale = 0;
+    webViewImpl->enableDeviceEmulation(params);
+    frameView->layout();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 2.0, frameView, visualViewport);
+    EXPECT_EQ(originalConstraints.initialScale, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().initialScale);
+    EXPECT_EQ(originalConstraints.minimumScale, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().minimumScale);
+    EXPECT_EQ(originalConstraints.maximumScale, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().maximumScale);
+
+    // Same behavior for disabling emulation after scale override.
+    params.visualViewportScale = 3.0;
+    webViewImpl->enableDeviceEmulation(params);
+    frameView->layout();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 3.0, frameView, visualViewport);
+    EXPECT_EQ(3.0, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().initialScale);
+    EXPECT_EQ(3.0, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().minimumScale);
+    EXPECT_EQ(3.0, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().maximumScale);
+
+    webViewImpl->disableDeviceEmulation();
+    EXPECT_SCROLL_AND_SCALE(DoublePoint(0, 0), DoublePoint(0, 0), 1.0, frameView, visualViewport);
+    EXPECT_EQ(originalConstraints.initialScale, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().initialScale);
+    EXPECT_EQ(originalConstraints.minimumScale, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().minimumScale);
+    EXPECT_EQ(originalConstraints.maximumScale, webViewImpl->pageScaleConstraintsSet().userAgentConstraints().maximumScale);
+}
+
 TEST_F(WebViewTest, ExitingDeviceEmulationResetsPageScale)
 {
     URLTestHelpers::registerMockedURLFromBaseURL(WebString::fromUTF8(m_baseURL.c_str()), WebString::fromUTF8("200-by-300.html"));