Remove the limitation that zoom can't go beyond overview scale.

Also scales the zoom level when zoom density changes.

issue: 3494868
Change-Id: I23ef9e1bad9c042ca0edf05dce60454b17eb0ade

core/java/android/webkit/ZoomManager.java

@@ -227,10 +227,13 @@ class ZoomManager {
         assert density > 0;
 
         if (Math.abs(density - mDefaultScale) > MINIMUM_SCALE_INCREMENT) {
+            // Remember the current zoom density before it gets changed.
+            final float originalDefault = mDefaultScale;
             // set the new default density
             setDefaultZoomScale(density);
+            float scaleChange = (originalDefault > 0.0) ? density / originalDefault: 1.0f;
             // adjust the scale if it falls outside the new zoom bounds
-            setZoomScale(mActualScale, true);
+            setZoomScale(mActualScale * scaleChange, true);
         }
     }
 
@@ -721,10 +724,7 @@ class ZoomManager {
         }
 
         public boolean onScale(ScaleGestureDetector detector) {
-            // Prevent scaling beyond overview scale.
-            float scale = Math.max(
-                    computeScaleWithLimits(detector.getScaleFactor() * mActualScale),
-                    getZoomOverviewScale());
+            float scale = computeScaleWithLimits(detector.getScaleFactor() * mActualScale);
             if (mPinchToZoomAnimating || willScaleTriggerZoom(scale)) {
                 mPinchToZoomAnimating = true;
                 // limit the scale change per step
@@ -780,13 +780,6 @@ class ZoomManager {
 
         // update mMinZoomScale if the minimum zoom scale is not fixed
         if (!mMinZoomScaleFixed) {
-            // when change from narrow screen to wide screen, the new viewWidth
-            // can be wider than the old content width. We limit the minimum
-            // scale to 1.0f. The proper minimum scale will be calculated when
-            // the new picture shows up.
-            mMinZoomScale = Math.min(1.0f, (float) mWebView.getViewWidth()
-                    / (mWebView.drawHistory() ? mWebView.getHistoryPictureWidth()
-                            : mZoomOverviewWidth));
             // limit the minZoomScale to the initialScale if it is set
             if (mInitialScale > 0 && mInitialScale < mMinZoomScale) {
                 mMinZoomScale = mInitialScale;
@@ -823,7 +816,7 @@ class ZoomManager {
                 // Keep overview mode unchanged when rotating.
                 final float zoomOverviewScale = getZoomOverviewScale();
                 final float newScale = (mInZoomOverviewBeforeSizeChange) ?
-                    zoomOverviewScale : Math.max(mActualScale, zoomOverviewScale); 
+                    zoomOverviewScale : mActualScale;
                 setZoomScale(newScale, mUpdateTextWrap, true);
                 // update the zoom buttons as the scale can be changed
                 updateZoomPicker();
@@ -879,21 +872,15 @@ class ZoomManager {
             }
         }
 
-        if (!mMinZoomScaleFixed) {
-            mMinZoomScale = newZoomOverviewScale;
-        }
         // fit the content width to the current view for the first new picture
         // after first layout.
         boolean scaleHasDiff = exceedsMinScaleIncrement(newZoomOverviewScale, mActualScale);
-        // Make sure the actual scale is no less than zoom overview scale.
-        boolean scaleLessThanOverview =
-                (newZoomOverviewScale - mActualScale) >= MINIMUM_SCALE_INCREMENT;
         // Make sure mobile sites are correctly handled since mobile site will
         // change content width after rotating.
         boolean mobileSiteInOverview = mInZoomOverview &&
                 !exceedsMinScaleIncrement(newZoomOverviewScale, 1.0f);
         if (!mWebView.drawHistory() &&
-                (mInitialZoomOverview || scaleLessThanOverview || mobileSiteInOverview) &&
+                (mInitialZoomOverview || mobileSiteInOverview) &&
                 scaleHasDiff && zoomOverviewWidthChanged) {
             mInitialZoomOverview = false;
             setZoomScale(newZoomOverviewScale, !willScaleTriggerZoom(mTextWrapScale) &&
@@ -967,10 +954,11 @@ class ZoomManager {
                 mTextWrapScale = viewState.mTextWrapScale;
                 scale = viewState.mViewScale;
             } else {
-                scale = overviewScale;
-                if (!settings.getUseWideViewPort()
-                    || !settings.getLoadWithOverviewMode()) {
-                    scale = Math.max(viewState.mTextWrapScale, scale);
+                scale = mDefaultScale;
+                mTextWrapScale = mDefaultScale;
+                if (settings.getUseWideViewPort()
+                        && settings.getLoadWithOverviewMode()) {
+                    scale = Math.max(overviewScale, scale);
                 }
                 if (settings.isNarrowColumnLayout() &&
                     settings.getUseFixedViewport()) {
@@ -981,7 +969,7 @@ class ZoomManager {
             }
             boolean reflowText = false;
             if (!viewState.mIsRestored) {
-                if (settings.getUseFixedViewport()) {
+                if (settings.getUseFixedViewport() && settings.getLoadWithOverviewMode()) {
                     // Override the scale only in case of fixed viewport.
                     scale = Math.max(scale, overviewScale);
                     mTextWrapScale = Math.max(mTextWrapScale, overviewScale);