Add an option to process favicons.

This optimizes the size for UI display and strips animations.
Default disabled. This resolves #899.

application/palemoon/app/profile/palemoon.js

@@ -264,6 +264,9 @@ pref("browser.slowStartup.maxSamples", 5);
 pref("browser.enable_automatic_image_resizing", true);
 pref("browser.chrome.site_icons", true);
 pref("browser.chrome.favicons", true);
+// If enabled, will process favicons by drawing them on a canvas,
+// optimizing display size for the UI. This also strips animations.
+pref("browser.chrome.favicons.process", false);
 // browser.warnOnQuit == false will override all other possible prompts when quitting or restarting
 pref("browser.warnOnQuit", true);
 // browser.showQuitWarning specifically controls the quit warning dialog. We

application/palemoon/base/content/tabbrowser.xml

@@ -831,13 +831,40 @@
                               "-moz-resolution=" + size + "," + size;
             }
             if (sizedIconUrl != aTab.getAttribute("image")) {
-              if (browser.mIconURL) //PMed
+              if (browser.mIconURL)
                 aTab.setAttribute("image", sizedIconUrl);
               else
                 aTab.removeAttribute("image");
               this._tabAttrModified(aTab, ["image"]);
             }
 
+            if (Services.prefs.getBoolPref("browser.chrome.favicons.process")) {
+              let favImage = new Image;
+              favImage.src = browser.mIconURL;
+              var tabBrowser = this;
+              favImage.onload = function () {
+                try {
+                  // Draw the icon on a hidden canvas
+                  var canvas = document.createElementNS("http://www.w3.org/1999/xhtml", "canvas");
+                  var tabImg = document.getAnonymousElementByAttribute(aTab, "anonid", "tab-icon");
+                  var w = tabImg.boxObject.width;
+                  var h = tabImg.boxObject.height;
+                  canvas.width = w;
+                  canvas.height = h;
+                  var ctx = canvas.getContext('2d');
+                  ctx.drawImage(favImage, 0, 0, w, h);
+                  icon = canvas.toDataURL();
+                  browser.mIconURL = icon;
+                  aTab.setAttribute("image", icon);
+                }
+                catch (e) {
+                  console.warn("Processing of favicon failed.");
+                  // Canvas failed: icon remains as it was
+                }
+                tabBrowser._callProgressListeners(browser, "onLinkIconAvailable", [browser.mIconURL]);
+              }
+            }
+                
             this._callProgressListeners(browser, "onLinkIconAvailable", [browser.mIconURL]);
           ]]>
         </body>