Resize only the virtual viewport when the OSK triggers a resize.

content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java

Index: content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
index f3bd7259805dd3b53aa13dab667da64e6df83851..54d4dc1e6f4dba6a6312aeda59755507080a02c8 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
@@ -502,6 +502,7 @@ public class ContentViewCore implements
     private int mPhysicalBackingHeightPix;
     private int mTopControlsHeightPix;
     private boolean mTopControlsShrinkBlinkSize;
+    private int mViewportHeightWithOSKHiddenPix;
 
     // Cached copy of all positions and scales as reported by the renderer.
     private final RenderCoordinates mRenderCoordinates;
@@ -1088,6 +1089,14 @@ public class ContentViewCore implements
     }
 
     /**
+     * @return Viewport height when the OSK is hidden in physical pixels as set from onSizeChanged.
+     */
+    @CalledByNative
+    public int getViewportHeightWithOSKHiddenPix() {
+        return mViewportHeightWithOSKHiddenPix;
+    }
+
+    /**
      * @return Width of underlying physical surface.
      */
     @CalledByNative
@@ -1619,13 +1628,45 @@ public class ContentViewCore implements
     public void onSizeChanged(int wPix, int hPix, int owPix, int ohPix) {
         if (getViewportWidthPix() == wPix && getViewportHeightPix() == hPix) return;
 
+        boolean displayRectChanged = false;
+        boolean triggeredByOSKShow = false;
+        if (!mFocusPreOSKViewportRect.isEmpty()) {
+            Rect rect = new Rect();
+            getContainerView().getWindowVisibleDisplayFrame(rect);
+            displayRectChanged = !rect.equals(mFocusPreOSKViewportRect);
+            // Only assume the OSK triggered the onSizeChanged if width was preserved.
+            triggeredByOSKShow = displayRectChanged
+                    && rect.width() == mFocusPreOSKViewportRect.width();
+        }
+
+        // triggeredByOSKShow is true if we are resizing to show the OSK. In this case,
+        // mViewportHeightWithOSKHiddenPix is mViewportHeightPix because the OSK was originally
+        // hidden. Otherwise, we are either resizing to hide the OSK or the onSizeChanged is not
+        // triggered by OSK, in which case mViewportHeightWithoutOSK is hPix because there's no OSK
+        // to include in the height.
+        if (triggeredByOSKShow) {
+            mViewportHeightWithOSKHiddenPix = mViewportHeightPix;

[jdduke (slow), 2015/10/09 15:17:28]

Like I said, the current heuristic is less than perfect for guessing that this
is an OSK show. At some point we might need to tighten the logic for cases like
dual window (http://www.androidcentral.com/using-dual-window-lg-g4) where the
window is resized is a persistent way vertically, e.g., make sure the height
*decreases* for the OSK showing case.

+        } else {
+            mViewportHeightWithOSKHiddenPix = hPix;
+        }
+
         mViewportWidthPix = wPix;
         mViewportHeightPix = hPix;
         if (mNativeContentViewCore != 0) {
             nativeWasResized(mNativeContentViewCore);
         }
 
-        updateAfterSizeChanged();
+        mPopupZoomer.hide(false);
+
+        // Execute a delayed form focus operation because the OSK was brought
+        // up earlier.
+        if (triggeredByOSKShow) {
+            assert mWebContents != null;
+            mWebContents.scrollFocusedEditableNodeIntoView();
+        }
+        if (displayRectChanged) {
+            cancelRequestToScrollFocusedEditableNodeIntoView();
+        }
     }
 
     /**
@@ -1647,27 +1688,8 @@ public class ContentViewCore implements
     public void onOverdrawBottomHeightChanged(int overdrawHeightPix) {
     }
 
-    private void updateAfterSizeChanged() {
-        mPopupZoomer.hide(false);
-
-        // Execute a delayed form focus operation because the OSK was brought
-        // up earlier.
-        if (!mFocusPreOSKViewportRect.isEmpty()) {
-            Rect rect = new Rect();
-            getContainerView().getWindowVisibleDisplayFrame(rect);
-            if (!rect.equals(mFocusPreOSKViewportRect)) {
-                // Only assume the OSK triggered the onSizeChanged if width was preserved.
-                if (rect.width() == mFocusPreOSKViewportRect.width()) {
-                    assert mWebContents != null;
-                    mWebContents.scrollFocusedEditableNodeIntoView();
-                }
-                cancelRequestToScrollFocusedEditableNodeIntoView();
-            }
-        }
-    }
-
     private void cancelRequestToScrollFocusedEditableNodeIntoView() {
-        // Zero-ing the rect will prevent |updateAfterSizeChanged()| from
+        // Zero-ing the rect will prevent |onSizeChanged()| from
         // issuing the delayed form focus event.
         mFocusPreOSKViewportRect.setEmpty();
     }