Upstream oodles of Chrome for Android code into Chromium.

chrome/android/java_staging/src/org/chromium/chrome/browser/tab/ThumbnailTabHelper.java

Index: chrome/android/java_staging/src/org/chromium/chrome/browser/tab/ThumbnailTabHelper.java
diff --git a/chrome/android/java_staging/src/org/chromium/chrome/browser/tab/ThumbnailTabHelper.java b/chrome/android/java_staging/src/org/chromium/chrome/browser/tab/ThumbnailTabHelper.java
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@@ -0,0 +1,335 @@
+// 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.tab;
+
+import android.content.res.Resources;
+import android.graphics.Bitmap;
+import android.graphics.Bitmap.Config;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.Rect;
+import android.os.Handler;
+import android.text.TextUtils;
+import android.util.Log;
+
+import com.google.android.apps.chrome.R;
+
+import org.chromium.chrome.browser.ChromeActivity;
+import org.chromium.chrome.browser.EmptyTabObserver;
+import org.chromium.chrome.browser.Tab;
+import org.chromium.chrome.browser.TabObserver;
+import org.chromium.chrome.browser.UrlConstants;
+import org.chromium.chrome.browser.profiles.Profile;
+import org.chromium.chrome.browser.util.MathUtils;
+import org.chromium.content.browser.ContentReadbackHandler;
+import org.chromium.content.browser.ContentViewCore;
+import org.chromium.content_public.browser.GestureStateListener;
+import org.chromium.content_public.browser.WebContents;
+import org.chromium.ui.base.WindowAndroid;
+
+/**
+ * Handles capturing most visited thumbnails for a tab.
+ */
+public class ThumbnailTabHelper {
+
+    private static final String TAG = "ThumbnailTabHelper";
+
+    /** The general motivation for this value is giving the scrollbar fadeout
+     *  animation sufficient time to finish before the capture executes. */
+    private static final int THUMBNAIL_CAPTURE_DELAY_MS = 350;
+
+    private final Tab mTab;
+    private final Handler mHandler;
+
+    private final int mThumbnailWidth;
+    private final int mThumbnailHeight;
+
+    private ContentViewCore mContentViewCore;
+    private boolean mThumbnailCapturedForLoad;
+    private boolean mIsRenderViewHostReady;
+    private boolean mWasRenderViewHostReady;
+
+    private final Runnable mThumbnailRunnable = new Runnable() {
+        @Override
+        public void run() {
+            // http://crbug.com/461506 : Do not get thumbnail unless render view host is ready.
+            if (!mIsRenderViewHostReady) return;
+
+            if (mThumbnailCapturedForLoad) return;
+            // Prevent redundant thumbnail capture attempts.
+            mThumbnailCapturedForLoad = true;
+            if (!canUpdateHistoryThumbnail()) {
+                // Allow a hidden tab to re-attempt capture in the future via |show()|.
+                mThumbnailCapturedForLoad = !mTab.isHidden();
+                return;
+            }
+            if (!shouldUpdateThumbnail()) return;
+
+            // Scale the image so we're not copying more than we need to (from
+            // the GPU).
+            int[] dim = new int[] {
+                mTab.getWidth(), mTab.getHeight()
+            };
+            MathUtils.scaleToFitTargetSize(dim, mThumbnailWidth, mThumbnailHeight);
+
+            ContentReadbackHandler readbackHandler = getActivity().getContentReadbackHandler();
+            if (readbackHandler == null || mTab.getContentViewCore() == null) return;
+            final String requestedUrl = mTab.getUrl();
+            ContentReadbackHandler.GetBitmapCallback bitmapCallback =
+                    new ContentReadbackHandler.GetBitmapCallback() {
+                        @Override
+                        public void onFinishGetBitmap(Bitmap bitmap, int response) {
+                            // Ensure that the URLs match for the requested page, and ensure
+                            // that the page is still valid for thumbnail capturing (i.e.
+                            // not showing an error page).
+                            if (bitmap == null
+                                    || !TextUtils.equals(requestedUrl, mTab.getUrl())
+                                    || !mThumbnailCapturedForLoad
+                                    || !canUpdateHistoryThumbnail()) {
+                                return;
+                            }
+                            updateHistoryThumbnail(bitmap);
+                            bitmap.recycle();
+                        }
+                    };
+            readbackHandler.getContentBitmapAsync(1, new Rect(0, 0, dim[0], dim[1]),
+                    mTab.getContentViewCore(), Bitmap.Config.ARGB_8888, bitmapCallback);
+        }
+    };
+
+    private final TabObserver mTabObserver = new EmptyTabObserver() {
+        @Override
+        public void onContentChanged(Tab tab) {
+            ThumbnailTabHelper.this.onContentChanged();
+        }
+
+        @Override
+        public void onCrash(Tab tab, boolean sadTabShown) {
+            cancelThumbnailCapture();
+        }
+
+        @Override
+        public void onPageLoadStarted(Tab tab) {
+            cancelThumbnailCapture();
+            mThumbnailCapturedForLoad = false;
+        }
+
+        @Override
+        public void onPageLoadFinished(Tab tab) {
+            rescheduleThumbnailCapture();
+        }
+
+        @Override
+        public void onPageLoadFailed(Tab tab, int errorCode) {
+            cancelThumbnailCapture();
+        }
+
+        @Override
+        public void onShown(Tab tab) {
+            // For tabs opened in the background, they may finish loading prior to becoming visible
+            // and the thumbnail capture triggered as part of load finish will be skipped as the
+            // tab has nothing rendered.  To handle this case, we also attempt thumbnail capture
+            // when showing the tab to give it a better chance to have valid content.
+            rescheduleThumbnailCapture();
+        }
+
+        @Override
+        public void onClosingStateChanged(Tab tab, boolean closing) {
+            if (closing) cancelThumbnailCapture();
+        }
+
+        @Override
+        public void onDestroyed(Tab tab) {
+            mTab.removeObserver(mTabObserver);
+            if (mContentViewCore != null) {
+                mContentViewCore.removeGestureStateListener(mGestureListener);
+                mContentViewCore = null;
+            }
+        }
+
+        @Override
+        public void onDidStartProvisionalLoadForFrame(
+                Tab tab, long frameId, long parentFrameId, boolean isMainFrame, String validatedUrl,
+                boolean isErrorPage, boolean isIframeSrcdoc) {
+            if (isMainFrame) {
+                mWasRenderViewHostReady = mIsRenderViewHostReady;
+                mIsRenderViewHostReady = false;
+            }
+        }
+
+        @Override
+        public void onDidFailLoad(
+                Tab tab, boolean isProvisionalLoad, boolean isMainFrame, int errorCode,
+                String description, String failingUrl) {
+            // For a case that URL overriding happens, we should recover |mIsRenderViewHostReady| to
+            // its old value to enable capturing thumbnail of the current page.
+            // If this failure shows an error page, capturing thumbnail will be denied anyway in
+            // canUpdateHistoryThumbnail().
+            if (isProvisionalLoad && isMainFrame) mIsRenderViewHostReady = mWasRenderViewHostReady;
+        }
+
+        @Override
+        public void onDidCommitProvisionalLoadForFrame(
+                Tab tab, long frameId, boolean isMainFrame, String url, int transitionType) {
+            if (isMainFrame) mIsRenderViewHostReady = true;
+        }
+    };
+
+    private GestureStateListener mGestureListener = new GestureStateListener() {
+        @Override
+        public void onFlingStartGesture(int vx, int vy, int scrollOffsetY, int scrollExtentY) {
+            cancelThumbnailCapture();
+        }
+
+        @Override
+        public void onFlingEndGesture(int scrollOffsetY, int scrollExtentY) {
+            rescheduleThumbnailCapture();
+        }
+
+        @Override
+        public void onScrollStarted(int scrollOffsetY, int scrollExtentY) {
+            cancelThumbnailCapture();
+        }
+
+        @Override
+        public void onScrollEnded(int scrollOffsetY, int scrollExtentY) {
+            rescheduleThumbnailCapture();
+        }
+    };
+
+    /**
+     * Creates a thumbnail tab helper for the given tab.
+     * @param tab The Tab whose thumbnails will be generated by this helper.
+     */
+    public static void createForTab(Tab tab) {
+        new ThumbnailTabHelper(tab);
+    }
+
+    /**
+     * Constructs the thumbnail tab helper for a given Tab.
+     * @param tab The Tab whose thumbnails will be generated by this helper.
+     */
+    private ThumbnailTabHelper(Tab tab) {
+        mTab = tab;
+        mTab.addObserver(mTabObserver);
+
+        mHandler = new Handler();
+
+        Resources res = tab.getWindowAndroid().getApplicationContext().getResources();
+        mThumbnailWidth = res.getDimensionPixelSize(R.dimen.most_visited_thumbnail_width);
+        mThumbnailHeight = res.getDimensionPixelSize(R.dimen.most_visited_thumbnail_height);
+
+        onContentChanged();
+    }
+
+    private void onContentChanged() {
+        if (mContentViewCore != null) {
+            mContentViewCore.removeGestureStateListener(mGestureListener);
+        }
+
+        mContentViewCore = mTab.getContentViewCore();
+        if (mContentViewCore != null) {
+            mContentViewCore.addGestureStateListener(mGestureListener);
+            nativeInitThumbnailHelper(mContentViewCore.getWebContents());
+        }
+    }
+
+    private ChromeActivity getActivity() {
+        WindowAndroid window = mTab.getWindowAndroid();
+        return (ChromeActivity) window.getActivity().get();
+    }
+
+    private void cancelThumbnailCapture() {
+        mHandler.removeCallbacks(mThumbnailRunnable);
+    }
+
+    private void rescheduleThumbnailCapture() {
+        if (mThumbnailCapturedForLoad) return;
+        cancelThumbnailCapture();
+        // Capture will be rescheduled when the GestureStateListener receives a
+        // scroll or fling end notification.
+        if (mTab.getContentViewCore() != null
+                && mTab.getContentViewCore().isScrollInProgress()) {
+            return;
+        }
+        mHandler.postDelayed(mThumbnailRunnable, THUMBNAIL_CAPTURE_DELAY_MS);
+    }
+
+    private boolean shouldUpdateThumbnail() {
+        return nativeShouldUpdateThumbnail(mTab.getProfile(), mTab.getUrl());
+    }
+
+    private void updateThumbnail(Bitmap bitmap) {
+        if (mTab.getContentViewCore() != null) {
+            final boolean atTop = mTab.getContentViewCore().computeVerticalScrollOffset() == 0;
+            nativeUpdateThumbnail(mTab.getWebContents(), bitmap, atTop);
+        }
+    }
+
+    private boolean canUpdateHistoryThumbnail() {
+        String url = mTab.getUrl();
+        if (url.startsWith(UrlConstants.CHROME_SCHEME)
+                || url.startsWith(UrlConstants.CHROME_NATIVE_SCHEME)) {
+            return false;
+        }
+        return mTab.isReady()
+                && !mTab.isShowingErrorPage()
+                && !mTab.isHidden()
+                && !mTab.isShowingSadTab()
+                && !mTab.isShowingInterstitialPage()
+                && mTab.getProgress() == 100
+                && mTab.getWidth() > 0
+                && mTab.getHeight() > 0;
+    }
+
+    private void updateHistoryThumbnail(Bitmap bitmap) {
+        if (mTab.isIncognito()) return;
+
+        // TODO(yusufo): It will probably be faster and more efficient on resources to do this on
+        // the native side, but the thumbnail_generator code has to be refactored a bit to allow
+        // creating a downsized version of a bitmap progressively.
+        if (bitmap.getWidth() != mThumbnailWidth
+                || bitmap.getHeight() != mThumbnailHeight
+                || bitmap.getConfig() != Config.ARGB_8888) {
+            try {
+                int[] dim = new int[] {
+                        bitmap.getWidth(), bitmap.getHeight()
+                };
+                // If the thumbnail size is small compared to the bitmap size downsize in
+                // two stages. This makes the final quality better.
+                float scale = Math.max(
+                        (float) mThumbnailWidth / dim[0],
+                        (float) mThumbnailHeight / dim[1]);
+                int adjustedWidth = (scale < 1)
+                        ? mThumbnailWidth * (int) (1 / Math.sqrt(scale)) : mThumbnailWidth;
+                int adjustedHeight = (scale < 1)
+                        ? mThumbnailHeight * (int) (1 / Math.sqrt(scale)) : mThumbnailHeight;
+                scale = MathUtils.scaleToFitTargetSize(dim, adjustedWidth, adjustedHeight);
+                // Horizontally center the source bitmap in the final result.
+                float leftOffset = (adjustedWidth - dim[0]) / 2.0f / scale;
+                Bitmap tmpBitmap = Bitmap.createBitmap(adjustedWidth,
+                        adjustedHeight, Config.ARGB_8888);
+                Canvas c = new Canvas(tmpBitmap);
+                c.scale(scale, scale);
+                c.drawBitmap(bitmap, leftOffset, 0, new Paint(Paint.FILTER_BITMAP_FLAG));
+                if (scale < 1) {
+                    tmpBitmap = Bitmap.createScaledBitmap(tmpBitmap,
+                            mThumbnailWidth, mThumbnailHeight, true);
+                }
+                updateThumbnail(tmpBitmap);
+                tmpBitmap.recycle();
+            } catch (OutOfMemoryError ex) {
+                Log.w(TAG, "OutOfMemoryError while updating the history thumbnail.");
+            }
+        } else {
+            updateThumbnail(bitmap);
+        }
+    }
+
+    private static native void nativeInitThumbnailHelper(WebContents webContents);
+    private static native void nativeUpdateThumbnail(
+            WebContents webContents, Bitmap bitmap, boolean atTop);
+    private static native boolean nativeShouldUpdateThumbnail(Profile profile, String url);
+}