Bug 698371 - Move determineCropSize calls to the child for remote browsers. r=dao

toolkit/components/thumbnails/PageThumbUtils.jsm

@@ -13,6 +13,7 @@ const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);
 Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/Promise.jsm", this);
 
 this.PageThumbUtils = {
   // The default background color for page thumbnails.
@@ -67,11 +68,13 @@ this.PageThumbUtils = {
    * @return An array containing width, height and scale.
    */
   determineCropSize: function (aWindow, aCanvas) {
+    if (Cu.isCrossProcessWrapper(aWindow)) {
+      throw new Error('Do not pass cpows here.');
+    }
     let utils = aWindow.QueryInterface(Ci.nsIInterfaceRequestor)
                        .getInterface(Ci.nsIDOMWindowUtils);
     // aWindow may be a cpow, add exposed props security values.
-    let sbWidth = {__exposedProps__: {"value": "rw"}},
-      sbHeight = {__exposedProps__: {"value": "rw"}};
+    let sbWidth = {}, sbHeight = {};
 
     try {
       utils.getScrollbarSize(false, sbWidth, sbHeight);
@@ -83,20 +86,20 @@ this.PageThumbUtils = {
 
     // Even in RTL mode, scrollbars are always on the right.
     // So there's no need to determine a left offset.
-    let sw = aWindow.innerWidth - sbWidth.value;
-    let sh = aWindow.innerHeight - sbHeight.value;
+    let width = aWindow.innerWidth - sbWidth.value;
+    let height = aWindow.innerHeight - sbHeight.value;
 
     let {width: thumbnailWidth, height: thumbnailHeight} = aCanvas;
-    let scale = Math.min(Math.max(thumbnailWidth / sw, thumbnailHeight / sh), 1);
-    let scaledWidth = sw * scale;
-    let scaledHeight = sh * scale;
+    let scale = Math.min(Math.max(thumbnailWidth / width, thumbnailHeight / height), 1);
+    let scaledWidth = width * scale;
+    let scaledHeight = height * scale;
 
     if (scaledHeight > thumbnailHeight)
-      sh -= Math.floor(Math.abs(scaledHeight - thumbnailHeight) * scale);
+      height -= Math.floor(Math.abs(scaledHeight - thumbnailHeight) * scale);
 
     if (scaledWidth > thumbnailWidth)
-      sw -= Math.floor(Math.abs(scaledWidth - thumbnailWidth) * scale);
+      width -= Math.floor(Math.abs(scaledWidth - thumbnailWidth) * scale);
 
-    return [sw, sh, scale];
+    return [width, height, scale];
   }
 };

toolkit/components/thumbnails/PageThumbs.jsm

@@ -216,12 +216,9 @@ this.PageThumbs = {
   // participate in this service's telemetry, which is why this method exists.
   _captureToCanvas: function (aBrowser, aCanvas, aCallback) {
     if (aBrowser.isRemoteBrowser) {
-      let [sw, sh, scale] =
-        PageThumbUtils.determineCropSize(aBrowser.contentWindowAsCPOW, aCanvas);
       Task.spawn(function () {
         let data =
-          yield this._captureRemoteThumbnail(aBrowser, sw, sh, scale,
-                                             PageThumbUtils.THUMBNAIL_BG_COLOR);
+          yield this._captureRemoteThumbnail(aBrowser, aCanvas);
         let canvas = data.thumbnail;
         let ctx = canvas.getContext("2d");
         let imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);
@@ -234,7 +231,7 @@ this.PageThumbs = {
     }
 
     // Generate in-process content thumbnail
-    let [sw, sh, scale] =
+    let [width, height, scale] =
       PageThumbUtils.determineCropSize(aBrowser.contentWindow, aCanvas);
     let ctx = aCanvas.getContext("2d");
 
@@ -244,7 +241,7 @@ this.PageThumbs = {
 
     try {
       // Draw the window contents to the canvas.
-      ctx.drawWindow(aBrowser.contentWindow, 0, 0, sw, sh,
+      ctx.drawWindow(aBrowser.contentWindow, 0, 0, width, height,
                      PageThumbUtils.THUMBNAIL_BG_COLOR,
                      ctx.DRAWWINDOW_DO_NOT_FLUSH);
     } catch (e) {
@@ -258,18 +255,13 @@ this.PageThumbs = {
   },
 
   /**
-   * Request a thumbnail using requested bounds and scale factor.
-   * @param aWidth - (optional) a width value less than or equal to the
-   *   innerWidth of the dom window. Defaults to the visible frame.
-   * @param aHeight - (optional) a height value less than or equal to the
-   *   innerHeight of the dom window. Defaults to the visible frame.
-   * @param aScaleFactor - (optional) 0.0 - 1.0 scale factor applied to the
-   *   returned thumbnail. Defaults to 1.0.
-   * @param aCssBackground - (optional) a css '#fff' color value to use as
-   *   the background color of the thumbnail.
+   * Asynchrnously render an appropriately scaled thumbnail to canvas.
+   *
+   * @param aBrowser The browser to capture a thumbnail from.
+   * @param aCanvas The canvas to draw to.
+   * @return a promise
    */
-  _captureRemoteThumbnail: function (aBrowser,  aWidth, aHeight,
-                                     aScaleFactor, aCssBackground) {
+  _captureRemoteThumbnail: function (aBrowser, aCanvas) {
     let deferred = Promise.defer();
 
     // The index we send with the request so we can identify the
@@ -308,18 +300,13 @@ this.PageThumbs = {
       // xxx wish there was a way to skip this encoding step
       reader.readAsDataURL(imageBlob);
     }
-    mm.addMessageListener("Browser:Thumbnail:Response", thumbFunc);
 
     // Send a thumbnail request
-    let width = aWidth || 0;
-    let height = aHeight || 0;
-    let scale = aScaleFactor || 1.0;
-    let background = aCssBackground || "#fff";
+    mm.addMessageListener("Browser:Thumbnail:Response", thumbFunc);
     mm.sendAsyncMessage("Browser:Thumbnail:Request", {
-      width: width,
-      height: height,
-      scale: scale,
-      background: background,
+      canvasWidth: aCanvas.width,
+      canvasHeight: aCanvas.height,
+      background: PageThumbUtils.THUMBNAIL_BG_COLOR,
       id: index
     });
 

toolkit/content/browser-child.js

@@ -11,7 +11,8 @@ Cu.import('resource://gre/modules/XPCOMUtils.jsm');
 Cu.import("resource://gre/modules/RemoteAddonsChild.jsm");
 Cu.import("resource://gre/modules/Timer.jsm");
 
-const HTML_NAMESPACE = "http://www.w3.org/1999/xhtml";
+XPCOMUtils.defineLazyModuleGetter(this, "PageThumbUtils",
+  "resource://gre/modules/PageThumbUtils.jsm");
 
 #ifdef MOZ_CRASHREPORTER
 XPCOMUtils.defineLazyServiceGetter(this, "CrashReporter",
@@ -374,19 +375,20 @@ addMessageListener("UpdateCharacterSet", function (aMessage) {
  * Remote thumbnail request handler for PageThumbs thumbnails.
  */
 addMessageListener("Browser:Thumbnail:Request", function (aMessage) {
-  let thumbnail = content.document.createElementNS(HTML_NAMESPACE, "canvas");
+  let thumbnail = content.document.createElementNS(PageThumbUtils.HTML_NAMESPACE,
+                                                   "canvas");
   thumbnail.mozOpaque = true;
   thumbnail.mozImageSmoothingEnabled = true;
 
-  // width and height are crop dims
-  let width = aMessage.data.width || content.innerWidth;
-  let height = aMessage.data.height || content.innerHeight;
-  thumbnail.width = Math.round(width * aMessage.data.scale);
-  thumbnail.height = Math.round(height * aMessage.data.scale);
+  thumbnail.width = aMessage.data.canvasWidth;
+  thumbnail.height = aMessage.data.canvasHeight;
+
+  let [width, height, scale] =
+    PageThumbUtils.determineCropSize(content, thumbnail);
 
   let ctx = thumbnail.getContext("2d");
   ctx.save();
-  ctx.scale(aMessage.data.scale, aMessage.data.scale);
+  ctx.scale(scale, scale);
   ctx.drawWindow(content, 0, 0, width, height,
                  aMessage.data.background,
                  ctx.DRAWWINDOW_DO_NOT_FLUSH);