Bug 1201416 - Remove incorrect call to setResolution. r=snorp

The call to setResolution has (I believe) not been needed since bug 732971. Prior
to that resolutions used to be applied on the root document in Fennec, and so
browser.js would have to reapply the desired resolution on every tabswitch.
After that bug, the resolution was saved on the content documents for each tab
and so browser.js no longer needed to reapply the resolution. Until recently
doing this was redundant but harmless.

With bug 1180267 though the browser.js code that tracks the resolution may have
the wrong resolution initially, because that is determined in C++ code. Only
after the Java-side code process the setFirstPaintViewport message and sends
that information to browser.js does everything have the correct resolution. In
the case where a tab loaded in the background is brought into the foreground, the
tab-selected code runs before the setFirstPaintViewport code, and therefore uses
an incorrect resolution. This then screws up the viewport clamping code and causes
the page to get scrolled.

--HG--
extra : commitid : 3Ic2BinhkXO

mobile/android/chrome/content/browser.js

@@ -1055,9 +1055,6 @@ var BrowserApp = {
       return;
 
     aTab.setActive(true);
-    if (!AppConstants.MOZ_ANDROID_APZ) {
-      aTab.setResolution(aTab._zoom, true);
-    }
     this.contentDocumentChanged();
     this.deck.selectedPanel = aTab.browser;
     // Focus the browser so that things like selection will be styled correctly.