Implement link selection on alt+mouse drag.

third_party/WebKit/Source/platform/testing/UnitTestHelpers.cpp

Index: third_party/WebKit/Source/platform/testing/UnitTestHelpers.cpp
diff --git a/third_party/WebKit/Source/platform/testing/UnitTestHelpers.cpp b/third_party/WebKit/Source/platform/testing/UnitTestHelpers.cpp
index 814a7f7150012d4cd85c2493031e8d990bbe3768..36f6123b3b247bff4921fbc551fef7fe91781b9f 100644
--- a/third_party/WebKit/Source/platform/testing/UnitTestHelpers.cpp
+++ b/third_party/WebKit/Source/platform/testing/UnitTestHelpers.cpp
@@ -30,6 +30,7 @@
 #include "base/message_loop/message_loop.h"
 #include "base/path_service.h"
 #include "platform/SharedBuffer.h"
+#include "platform/Timer.h"
 #include "public/platform/FilePathConversion.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebString.h"
@@ -48,6 +49,22 @@ void runPendingTasks()
     enterRunLoop();
 }
 
+struct QuitTask {
+    void timerFired(Timer<QuitTask>*)
+    {
+        // We cannot just exit loop here, because we may be halfway through the task queue.
+        Platform::current()->currentThread()->getWebTaskRunner()->postTask(BLINK_FROM_HERE, bind(&exitRunLoop));
+    }
+};
+
+void waitForDeferredTasks(double seconds)
+{
+    // Pending tasks include Timers that have been scheduled.
+    Timer<QuitTask> quitOnTimeout(new QuitTask, &QuitTask::timerFired);
+    quitOnTimeout.startOneShot(seconds, BLINK_FROM_HERE);
+    testing::enterRunLoop();
+}
+
 String blinkRootDir()
 {
     base::FilePath path;