Do screenshot capture async for share intents.

chrome/android/javatests/src/org/chromium/chrome/browser/BlockingFileProviderTest.java

Index: chrome/android/javatests/src/org/chromium/chrome/browser/BlockingFileProviderTest.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/BlockingFileProviderTest.java b/chrome/android/javatests/src/org/chromium/chrome/browser/BlockingFileProviderTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..c66a577662134f4e52cec180cef29c4d7647abf8
--- /dev/null
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/BlockingFileProviderTest.java
@@ -0,0 +1,93 @@
+// Copyright 2016 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;
+
+import android.content.Context;
+import android.net.Uri;
+import android.os.AsyncTask;
+import android.os.ParcelFileDescriptor;
+import android.test.suitebuilder.annotation.LargeTest;
+import android.test.suitebuilder.annotation.SmallTest;
+
+import org.chromium.content.browser.test.NativeLibraryTestBase;
+
+import java.io.FileNotFoundException;
+
+/**
+ * Tests working of BlockingFileProvider.
+ *
+ * The openFile should be blocked till notify is called. These tests can timeout if the notify does
+ * not work correctly.
+ */
+public class BlockingFileProviderTest extends NativeLibraryTestBase {
+    private ParcelFileDescriptor openFileFromProvider(Uri uri) {
+        BlockingFileProvider provider = new BlockingFileProvider();
+        ParcelFileDescriptor file = null;
+        try {
+            provider.openFile(uri, "r");
+        } catch (FileNotFoundException e) {
+            assert false : "Failed to open file.";
+        }
+        return file;
+    }
+
+    @SmallTest
+    public void testOpenFileWhenReady() {
+        Uri uri = BlockingFileProvider.generateUriAndBlockAccess(getInstrumentation().getContext());
+        BlockingFileProvider.notifyFileReady(uri, null);
+        ParcelFileDescriptor file = openFileFromProvider(uri);
+        // File should be null because the notify passes a null file uri.
+        assertNull(file);
+    }
+
+    @LargeTest
+    public void testBlockedOnAsyncNotify() {
+        final Context context = getInstrumentation().getContext();
+        final Uri uri = BlockingFileProvider.generateUriAndBlockAccess(context);
+        new AsyncTask<Void, Void, Void>() {
+            @Override
+            protected Void doInBackground(Void... params) {
+                try {
+                    Thread.sleep(200);

[Ted C, 2016/08/27 00:22:12]

i think you can make this much shorter...we just want to make sure it works on
async notifies so 10 millis seems reasonable to me.  if this doesn't work then
it would timeout and the test would fail, so the shorter the runtime the better

[ssid, 2016/09/06 22:25:36]

Done.

+                } catch (InterruptedException e) {
+                    // Ignore exception.
+                }
+                BlockingFileProvider.notifyFileReady(uri, null);
+                return null;
+            }
+        }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
+        ParcelFileDescriptor file = openFileFromProvider(uri);
+        // File should be null because the notify passes a null file uri.
+        assertNull(file);
+    }
+
+    @LargeTest
+    public void testFileChanged() {
+        final Context context = getInstrumentation().getContext();
+        Uri uri1 = BlockingFileProvider.generateUriAndBlockAccess(context);
+        final Uri uri2 = BlockingFileProvider.generateUriAndBlockAccess(context);
+        new AsyncTask<Void, Void, Void>() {
+            @Override
+            protected Void doInBackground(Void... params) {
+                try {
+                    Thread.sleep(200);

[Ted C, 2016/08/27 00:22:12]

same timing comment

[ssid, 2016/09/06 22:25:36]

Done.

+                } catch (InterruptedException e) {
+                    // Ignore exception.
+                }
+                BlockingFileProvider.notifyFileReady(uri2, null);
+                return null;
+            }
+        }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
+
+        // This should be unblocked irrespective of when the second notify is called.
+        ParcelFileDescriptor file1 = openFileFromProvider(uri2);

[Ted C, 2016/08/27 00:22:12]

i find it odd that file1 == uri2,  I'd recommend making them match to make this
easier to read

[ssid, 2016/09/06 22:25:36]

Done.

+        assertNull(file1);
+
+        // This should not be blocked even without a notify since file was changed.
+        ParcelFileDescriptor file2 = openFileFromProvider(uri1);
+        // File should be null because the notify passes a null file uri.
+        assertNull(file2);
+    }
+}