CompositorViewHolder is source of truth for viewports

chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java b/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java
index 5855d3297cc718200f591b898a7caea998e96150..4828026c015462d989c8dfe5de7d3a7d6eb0a542 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java
@@ -78,17 +78,10 @@ public abstract class LayoutManager implements LayoutUpdateHost, LayoutProvider,
     private int mFullscreenToken = FullscreenManager.INVALID_TOKEN;
     private boolean mUpdateRequested;
 
-    // Sizing State
-    protected final RectF mLastViewportPx = new RectF();
-    protected final RectF mLastVisibleViewportPx = new RectF();
-    protected final RectF mLastFullscreenViewportPx = new RectF();
-
     // Used to store the visible viewport and not create a new Rect object every frame.
     private final RectF mCachedVisibleViewport = new RectF();
     private final RectF mCachedWindowViewport = new RectF();
 
-    protected float mHeightMinusBrowserControlsPx;
-
     private final RectF mCachedRect = new RectF();
     private final PointF mCachedPoint = new PointF();
 
@@ -100,14 +93,6 @@ public abstract class LayoutManager implements LayoutUpdateHost, LayoutProvider,
         mHost = host;
         mPxToDp = 1.f / mHost.getContext().getResources().getDisplayMetrics().density;
         mSceneChangeObservers = new ObserverList<SceneChangeObserver>();
-
-        int hostWidth = host.getWidth();
-        int hostHeight = host.getHeight();
-        mLastViewportPx.set(0, 0, hostWidth, hostHeight);
-        mLastVisibleViewportPx.set(0, 0, hostWidth, hostHeight);
-        mLastFullscreenViewportPx.set(0, 0, hostWidth, hostHeight);
-
-        mHeightMinusBrowserControlsPx = hostHeight;
     }
 
     /**
@@ -269,13 +254,7 @@ public abstract class LayoutManager implements LayoutUpdateHost, LayoutProvider,
             TabContentManager tabContentManager, ResourceManager resourceManager,
             ChromeFullscreenManager fullscreenManager) {
         getViewportPixel(mCachedVisibleViewport);
-        // TODO(mdjones): The concept of visible viewport is pretty confising since |viewport| can
-        // also take the browser controls into consideration; this should be made more clear.
-        // Furthermore, the below adjustments should not be necessary.
-        mCachedVisibleViewport.right = mCachedVisibleViewport.left + mHost.getWidth();
-        mCachedVisibleViewport.bottom = mCachedVisibleViewport.top + mHost.getHeight();
-
-        getViewportPixel(mCachedWindowViewport);
+        mHost.getWindowViewport(mCachedWindowViewport);
         return mActiveLayout.getUpdatedSceneLayer(mCachedWindowViewport, mCachedVisibleViewport,
                 layerTitleCache, tabContentManager, resourceManager, fullscreenManager);
     }
@@ -284,32 +263,16 @@ public abstract class LayoutManager implements LayoutUpdateHost, LayoutProvider,
      * Called when the viewport has been changed.  Override this to be notified when
      * {@link #pushNewViewport(Rect, Rect, int)} calls actually change the current viewport.
      */
-    protected void onViewportChanged() {
+    public void onViewportChanged() {
         if (getActiveLayout() != null) {
-            getActiveLayout().sizeChanged(mLastVisibleViewportPx, mLastFullscreenViewportPx,
-                    mHeightMinusBrowserControlsPx, getOrientation());
+            mHost.getWindowViewport(mCachedWindowViewport);
+            mHost.getVisibleViewport(mCachedVisibleViewport);
+            getActiveLayout().sizeChanged(mCachedVisibleViewport, mCachedWindowViewport,
+                    mHost.getHeightMinusBrowserControls(), getOrientation());
         }
     }
 
     /**
-     * Should be called from an external source when the viewport changes.  {@code viewport} and
-     * {@code visibleViewport} are different, as the browser controls might be covering part of the
-     * viewport but a {@link Layout} might want to consume the whole space (or not).
-     * @param viewport               The new viewport in px.
-     * @param visibleViewport        The new visible viewport in px.
-     * @param heightMinusBrowserControls The height of the viewport minus the browser controls.
-     */
-    public final void pushNewViewport(
-            RectF viewport, RectF visibleViewport, int heightMinusBrowserControls) {
-        mLastViewportPx.set(viewport);
-        mLastVisibleViewportPx.set(visibleViewport);
-        mLastFullscreenViewportPx.set(0, 0, mHost.getWidth(), mHost.getHeight());
-        mHeightMinusBrowserControlsPx = heightMinusBrowserControls;
-
-        onViewportChanged();
-    }
-
-    /**
      * @return The default {@link Layout} to show when {@link Layout}s get hidden and the next
      *         {@link Layout} to show isn't known.
      */
@@ -348,17 +311,15 @@ public abstract class LayoutManager implements LayoutUpdateHost, LayoutProvider,
     @Override
     public void getViewportPixel(RectF rect) {
         if (getActiveLayout() == null) {
-            rect.set(mLastViewportPx);
+            mHost.getWindowViewport(rect);
             return;
         }
 
         final int flags = getActiveLayout().getSizingFlags();
         if ((flags & SizingFlags.REQUIRE_FULLSCREEN_SIZE) != 0) {
-            rect.set(mLastFullscreenViewportPx);
-        } else if ((flags & SizingFlags.ALLOW_TOOLBAR_HIDE) != 0) {
-            rect.set(mLastViewportPx);
+            mHost.getWindowViewport(rect);
         } else {
-            rect.set(mLastVisibleViewportPx);
+            mHost.getVisibleViewport(rect);
         }
     }