[DevTools] More UX fixes in Device Mode.

third_party/WebKit/Source/devtools/front_end/emulation/DeviceModeView.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @constructor
  * @extends {WebInspector.VBox}
  */
 WebInspector.DeviceModeView = function()
 {
@@ skipping 436 matching lines @@
                     ctx.drawImage(image, rect.left, rect.top, rect.width, rect.height);
                     callback();
                 }
             }
 
             /**
              * @this {WebInspector.DeviceModeView}
              */
             function paintScreenshot()
             {
+                ctx.strokeStyle = "hsla(0, 0%, 98%, 0.5)";
+                ctx.lineWidth = 1;
+                ctx.setLineDash([10, 10]);
+                ctx.strokeRect(screenRect.left + 1, screenRect.top + 1, screenRect.width - 2, screenRect.height - 2);
                 var pageImage = new Image();
                 pageImage.src = "data:image/png;base64," + content;
                 ctx.drawImage(pageImage,
                               visiblePageRect.left,
                               visiblePageRect.top,
-                              visiblePageRect.width,
-                              visiblePageRect.height);
+                              Math.min(pageImage.naturalWidth, screenRect.width),
+                              Math.min(pageImage.naturalHeight, screenRect.height));
                 var mainFrame = mainTarget.resourceTreeModel.mainFrame;
                 var fileName = mainFrame ? mainFrame.url.trimURL().removeURLFragment() : "";
                 if (this._model.type() === WebInspector.DeviceModeModel.Type.Device)
                     fileName += WebInspector.UIString("(%s)", this._model.device().title);
                 // Trigger download.
                 var link = createElement("a");
                 link.download = fileName + ".png";
                 link.href = canvas.toDataURL("image/png");
                 link.click();
             }
@@ skipping 97 matching lines @@
     /**
      * @param {number} size
      */
     _onMarkerClick: function(size)
     {
         this._applyCallback.call(null, size);
     },
 
     __proto__: WebInspector.VBox.prototype
 }