Gallery: Add animation when zooming pictures.

BUG=245926
TEST=manually

Review URL: https://codereview.chromium.org/395083002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@283519 0039d316-1c4b-4281-b951-d872f2087c98

ui/file_manager/gallery/js/image_editor/image_view.js

@@ -125,6 +125,17 @@ ImageView.prototype.draw = function() {
   }
 };
 
+/**
+ * Applies the viewport change that does not affect the screen cache size (zoom
+ * change or offset change) with animation.
+ */
+ImageView.prototype.applyViewportChange = function() {
+  this.setTransform(
+      this.screenImage_,
+      new ImageView.Effect.None(),
+      ImageView.Effect.DEFAULT_DURATION);
+};
+
 /**
  * @return {number} The cache generation.
  */

ui/file_manager/gallery/js/image_editor/viewport.js

@@ -98,7 +98,6 @@ Viewport.prototype.setZoomIndex = function(zoomIndex) {
 
   this.zoomIndex_ = zoomIndex;
   this.zoom_ = Viewport.ZOOM_RATIOS[zoomIndex];
-  this.invalidateCaches();
 };
 
 /**

ui/file_manager/gallery/js/slide_mode.js

@@ -869,14 +869,14 @@ SlideMode.prototype.onKeyDown = function(event) {
     case 'Ctrl-U+00BB':  // Ctrl+'=' zoom in.
       if (!this.isEditing()) {
         this.viewport_.setZoomIndex(this.viewport_.getZoomIndex() + 1);
-        this.imageView_.draw();
+        this.imageView_.applyViewportChange();
       }
       break;
 
     case 'Ctrl-U+00BD':  // Ctrl+'-' zoom out.
       if (!this.isEditing()) {
         this.viewport_.setZoomIndex(this.viewport_.getZoomIndex() - 1);
-        this.imageView_.draw();
+        this.imageView_.applyViewportChange();
       }
       break;
   }