Fix size estimation for prerender in custom tabs

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java

 // 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.
 
 package org.chromium.chrome.browser.customtabs;
 
 import android.app.ActivityManager;
 import android.app.Application;
 import android.content.ComponentName;
 import android.content.Context;
@@ skipping 71 matching lines @@
 
     private static AtomicReference<CustomTabsConnection> sInstance =
             new AtomicReference<CustomTabsConnection>();
 
     private static final class PrerenderedUrlParams {
         public final IBinder mSession;
         public final WebContents mWebContents;
         public final String mUrl;
         public final String mReferrer;
         public final Bundle mExtras;
+        public final Point mSize;
 
         PrerenderedUrlParams(IBinder session, WebContents webContents, String url, String referrer,
-                Bundle extras) {
+                Point size, Bundle extras) {
             mSession = session;
             mWebContents = webContents;
             mUrl = url;
             mReferrer = referrer;
+            mSize = size;
             mExtras = extras;
         }
     }
 
     private static final class PredictionStats {
         private static final long MIN_DELAY = 100;
         private static final long MAX_DELAY = 10000;
         private long mLastRequestTimestamp = -1;
         private long mDelayMs = MIN_DELAY;
 
@@ skipping 318 matching lines @@
      * hand, not cancelling the previous prerender leads to wasted resources, as
      * a WebContents is lingering. This can be solved by requiring applications
      * to call mayLaunchUrl(null) to cancel a current prerender before 2, that
      * is for a mispredict.
      *
      * @param session The Binder object identifying a session.
      * @param url The URL the WebContents is for.
      * @param referrer The referrer to use for |url|.
      * @return The prerendered WebContents, or null.
      */
-    WebContents takePrerenderedUrl(IBinder session, String url, String referrer) {
+    WebContents takePrerenderedUrl(IBinder session, String url, String referrer, Point size) {
         ThreadUtils.assertOnUiThread();
         if (mPrerender == null || session == null || !session.equals(mPrerender.mSession)) {
             return null;
         }
         WebContents webContents = mPrerender.mWebContents;
         String prerenderedUrl = mPrerender.mUrl;
         String prerenderReferrer = mPrerender.mReferrer;
+        size.x = mPrerender.mSize.x;
+        size.y = mPrerender.mSize.y;
         if (referrer == null) referrer = "";
         mPrerender = null;
         if (TextUtils.equals(prerenderedUrl, url)
                 && TextUtils.equals(prerenderReferrer, referrer)) {
             return webContents;
         }
         mExternalPrerenderHandler.cancelCurrentPrerender();
         webContents.destroy();
         return null;
     }
@@ skipping 211 matching lines @@
             mPrerender.mWebContents.destroy();
             mPrerender = null;
         }
         if (TextUtils.isEmpty(url)) return;
         Intent extrasIntent = new Intent();
         if (extras != null) extrasIntent.putExtras(extras);
         if (IntentHandler.getExtraHeadersFromIntent(extrasIntent) != null) return;
         if (mExternalPrerenderHandler == null) {
             mExternalPrerenderHandler = new ExternalPrerenderHandler();
         }
-        Point contentSize = estimateContentSize();
         Context context = mApplication.getApplicationContext();
         String referrer = IntentHandler.getReferrerUrlIncludingExtraHeaders(extrasIntent, context);
         if (referrer == null && getReferrerForSession(session) != null) {
             referrer = getReferrerForSession(session).getUrl();
         }
         if (referrer == null) referrer = "";
+        Point contentSize = estimateContentSize(true);
         WebContents webContents = mExternalPrerenderHandler.addPrerender(
                 Profile.getLastUsedProfile(), url, referrer, contentSize.x, contentSize.y);
         if (webContents != null) {
-            mPrerender = new PrerenderedUrlParams(session, webContents, url, referrer, extras);
+            mPrerender = new PrerenderedUrlParams(
+                    session, webContents, url, referrer, estimateContentSize(false), extras);

[Ted C, 2015/09/16 18:12:47]

why is this false?  Isn't this for prerendered contents?

         }
     }
 
     /**
      * Provides an estimate of the contents size.
      *
      * The estimate is likely to be incorrect. This is not a problem, as the aim
      * is to avoid getting a different layout and resources than needed at
      * render time.
+     * @param forPrerenderedContents Whether the size returned should be for prerendered web
+     *                               contents or for ContentViewCore. The former takes the web
+     *                               content size that doesn't include control conatiner height
+     *                               in dp, the latter includes the control container height and
+     *                               is in pixels.
      */
-    private Point estimateContentSize() {
+    private Point estimateContentSize(boolean forPrerenderedContents) {
         // The size is estimated as:
         // X = screenSizeX
         // Y = screenSizeY - top bar - bottom bar - custom tabs bar
         Point screenSize = new Point();
         WindowManager wm = (WindowManager) mApplication.getSystemService(Context.WINDOW_SERVICE);
         wm.getDefaultDisplay().getSize(screenSize);
         Resources resources = mApplication.getResources();
         int statusBarId = resources.getIdentifier("status_bar_height", "dimen", "android");
-        int navigationBarId = resources.getIdentifier("navigation_bar_height", "dimen", "android");
         try {
-            screenSize.y -=
-                    resources.getDimensionPixelSize(R.dimen.custom_tabs_control_container_height);
+            if (forPrerenderedContents) {
+                screenSize.y -= resources.getDimensionPixelSize(
+                        R.dimen.custom_tabs_control_container_height);
+            }
             screenSize.y -= resources.getDimensionPixelSize(statusBarId);
-            screenSize.y -= resources.getDimensionPixelSize(navigationBarId);
         } catch (Resources.NotFoundException e) {
             // Nothing, this is just a best effort estimate.
         }
+        if (forPrerenderedContents) {
+            float density = resources.getDisplayMetrics().density;
+            screenSize.x /= density;
+            screenSize.y /= density;
+        }
         return screenSize;
     }
 
     @VisibleForTesting
     void resetThrottling(int uid) {
         synchronized (mLock) {
             mUidToPredictionsStats.put(uid, new PredictionStats());
         }
     }
 }