Bug 1523844 Part 5: Add a test case to TestMobileViewportManager. r=bradwerth

Depends on D41104

Differential Revision: https://phabricator.services.mozilla.com/D41453

--HG--
extra : moz-landing-system : lando

gfx/layers/apz/test/gtest/mvm/TestMobileViewportManager.cpp

@@ -11,6 +11,7 @@
 
 #include "MobileViewportManager.h"
 #include "mozilla/MVMContext.h"
+#include "mozilla/dom/Event.h"
 
 using namespace mozilla;
 
@@ -40,11 +41,24 @@ class MockMVMContext : public MVMContext {
   MOCK_METHOD1(SetVisualViewportSize, void(const CSSSize& aSize));
   MOCK_METHOD0(UpdateDisplayPortMargins, void());
 
+  void SetMVM(MobileViewportManager* aMVM) { mMVM = aMVM; }
+
   // MVMContext method implementations.
   nsViewportInfo GetViewportInfo(const ScreenIntSize& aDisplaySize) const {
-    return nsViewportInfo(mDefaultScale, mMinScale, mMaxScale,
-                          mDisplaySize / mDeviceScale, mAutoSizeFlag,
-                          mAutoScaleFlag, mZoomFlag);
+    // This is a very basic approximation of what Document::GetViewportInfo()
+    // does in the most common cases.
+    // Ideally, we would invoke the algorithm in Document::GetViewportInfo()
+    // itself, but that would require refactoring it a bit to remove
+    // dependencies on the actual Document which we don't have available in
+    // this test harness.
+    CSSSize viewportSize = mDisplaySize / mDeviceScale;
+    if (mAutoSizeFlag == AutoSizeFlag::FixedSize) {
+      viewportSize = CSSSize(mFixedViewportWidth,
+                             mFixedViewportWidth * (float(mDisplaySize.height) /
+                                                    mDisplaySize.width));
+    }
+    return nsViewportInfo(mDefaultScale, mMinScale, mMaxScale, viewportSize,
+                          mAutoSizeFlag, mAutoScaleFlag, mZoomFlag);
   }
   CSSToLayoutDeviceScale CSSToDevPixelScale() const { return mDeviceScale; }
   float GetResolution() const { return mResolution; }
@@ -64,6 +78,7 @@ class MockMVMContext : public MVMContext {
   void SetResolutionAndScaleTo(float aResolution,
                                ResolutionChangeOrigin aOrigin) {
     mResolution = aResolution;
+    mMVM->ResolutionUpdated(aOrigin);
   }
   void Reflow(const CSSSize& aNewSize, const CSSSize& aOldSize,
               ResizeEventFlag aResizeEventFlag) {
@@ -78,6 +93,10 @@ class MockMVMContext : public MVMContext {
     mDefaultScale = aInitialScale;
     mAutoScaleFlag = AutoScaleFlag::FixedScale;
   }
+  void SetFixedViewportWidth(CSSCoord aWidth) {
+    mFixedViewportWidth = aWidth;
+    mAutoSizeFlag = AutoSizeFlag::FixedSize;
+  }
   void SetDisplaySize(const LayoutDeviceIntSize& aNewDisplaySize) {
     mDisplaySize = aNewDisplaySize;
   }
@@ -96,6 +115,7 @@ class MockMVMContext : public MVMContext {
   CSSToScreenScale mMinScale{0.25f};
   CSSToScreenScale mMaxScale{10.0f};
   CSSToLayoutDeviceScale mDeviceScale{1.0f};
+  CSSCoord mFixedViewportWidth;
   AutoSizeFlag mAutoSizeFlag = AutoSizeFlag::AutoSize;
   AutoScaleFlag mAutoScaleFlag = AutoScaleFlag::AutoScale;
   ZoomFlag mZoomFlag = ZoomFlag::AllowZoom;
@@ -106,13 +126,17 @@ class MockMVMContext : public MVMContext {
   float mResolution = 1.0f;
   CSSSize mICBSize;
   CSSSize mContentSize;
+
+  MobileViewportManager* mMVM = nullptr;
 };
 
 class MVMTester : public ::testing::Test {
  public:
   MVMTester()
       : mMVMContext(new MockMVMContext()),
-        mMVM(new MobileViewportManager(mMVMContext)) {}
+        mMVM(new MobileViewportManager(mMVMContext)) {
+    mMVMContext->SetMVM(mMVM.get());
+  }
 
   void Resize(const LayoutDeviceIntSize& aNewDisplaySize) {
     mMVMContext->SetDisplaySize(aNewDisplaySize);
@@ -150,3 +174,42 @@ TEST_F(MVMTester, ZoomBoundsRespectedAfterRotation_Bug1536755) {
   EXPECT_EQ(CSSSize(300, 600), mMVMContext->GetContentSize());
   EXPECT_EQ(1.0f, mMVMContext->GetResolution());
 }
+
+TEST_F(MVMTester, LandscapeToPortraitRotation_Bug1523844) {
+  // Set up initial conditions.
+  mMVMContext->SetDisplaySize(LayoutDeviceIntSize(300, 600));
+  // Set a layout function that simulates a page with a fixed
+  // content size that's as wide as the screen in one orientation
+  // (and wider in the other).
+  mMVMContext->SetLayoutFunction(
+      [](CSSSize aICBSize) { return CSSSize(600, 1200); });
+
+  // Simulate a "DOMMetaAdded" event being fired before calling
+  // SetInitialViewport(). This matches what typically happens
+  // during real usage (the MVM receives the "DOMMetaAdded"
+  // before the "load", and it's the "load" that calls
+  // SetInitialViewport()), and is important to trigger this
+  // bug, because it causes the MVM to be stuck with an
+  // "mRestoreResolution" (prior to the fix).
+  mMVM->HandleDOMMetaAdded();
+
+  // Perform an initial viewport computation and reflow, and
+  // sanity-check the results.
+  mMVM->SetInitialViewport();
+  EXPECT_EQ(CSSSize(300, 600), mMVMContext->GetICBSize());
+  EXPECT_EQ(CSSSize(600, 1200), mMVMContext->GetContentSize());
+  EXPECT_EQ(0.5f, mMVMContext->GetResolution());
+
+  // Rotate to landscape.
+  Resize(LayoutDeviceIntSize(600, 300));
+  EXPECT_EQ(CSSSize(600, 300), mMVMContext->GetICBSize());
+  EXPECT_EQ(CSSSize(600, 1200), mMVMContext->GetContentSize());
+  EXPECT_EQ(1.0f, mMVMContext->GetResolution());
+
+  // Rotate back to portrait and check that we have returned
+  // to the portrait resolution.
+  Resize(LayoutDeviceIntSize(300, 600));
+  EXPECT_EQ(CSSSize(300, 600), mMVMContext->GetICBSize());
+  EXPECT_EQ(CSSSize(600, 1200), mMVMContext->GetContentSize());
+  EXPECT_EQ(0.5f, mMVMContext->GetResolution());
+}

layout/base/MobileViewportManager.cpp

@@ -128,8 +128,7 @@ MobileViewportManager::HandleEvent(dom::Event* event) {
   event->GetType(type);
 
   if (type.Equals(DOM_META_ADDED)) {
-    MVM_LOG("%p: got a dom-meta-added event\n", this);
-    RefreshViewportSize(mPainted);
+    HandleDOMMetaAdded();
   } else if (type.Equals(DOM_META_CHANGED)) {
     MVM_LOG("%p: got a dom-meta-changed event\n", this);
     RefreshViewportSize(mPainted);
@@ -146,6 +145,11 @@ MobileViewportManager::HandleEvent(dom::Event* event) {
   return NS_OK;
 }
 
+void MobileViewportManager::HandleDOMMetaAdded() {
+  MVM_LOG("%p: got a dom-meta-added event\n", this);
+  RefreshViewportSize(mPainted);
+}
+
 NS_IMETHODIMP
 MobileViewportManager::Observe(nsISupports* aSubject, const char* aTopic,
                                const char16_t* aData) {

layout/base/MobileViewportManager.h

@@ -54,6 +54,11 @@ class MobileViewportManager final : public nsIDOMEventListener,
    */
   float ComputeIntrinsicResolution() const;
 
+  /* The only direct calls to this should be in test code.
+   * Normally, it gets called by HandleEvent().
+   */
+  void HandleDOMMetaAdded();
+
  private:
   void SetRestoreResolution(float aResolution);