Make sure the ash's host window is placed within the Xvfb's root wind…

…ow so that mouse can move correctly.

Enlarge the Xvfb's size to 1280x800 as there are several tests that require minimum width 1280.

BUG=538799
R=sky@chromium.org
TBR=thestig@chromium.org

Review URL: https://codereview.chromium.org/1389503002

Cr-Commit-Position: refs/heads/master@{#352357}

chrome/test/base/view_event_test_platform_part_chromeos.cc

@@ -4,11 +4,13 @@
 
 #include "chrome/test/base/view_event_test_platform_part.h"
 
+#include "ash/ash_switches.h"
 #include "ash/shell.h"
 #include "ash/shell_init_params.h"
 #include "ash/test/ash_test_helper.h"
 #include "ash/test/test_session_state_delegate.h"
 #include "ash/test/test_shell_delegate.h"
+#include "base/command_line.h"
 #include "chromeos/audio/cras_audio_handler.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/network/network_handler.h"
@@ -59,6 +61,8 @@ ViewEventTestPlatformPartChromeOS::ViewEventTestPlatformPartChromeOS(
   init_params.delegate = shell_delegate;
   init_params.context_factory = context_factory;
   init_params.blocking_pool = content::BrowserThread::GetBlockingPool();
+  base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
+      ash::switches::kAshHostWindowBounds, "0+0-1280x800");
   ash::Shell::CreateInstance(init_params);
   ash::test::AshTestHelper::GetTestSessionStateDelegate()->
       SetActiveUserSessionStarted(true);

testing/xvfb.py

@@ -83,7 +83,7 @@ def start_xvfb(env, build_dir, xvfb_path='Xvfb', display=':9'):
   openbox_proc = None
 
   try:
-    xvfb_cmd = [xvfb_path, display, '-screen', '0', '1024x768x24', '-ac',
+    xvfb_cmd = [xvfb_path, display, '-screen', '0', '1280x800x24', '-ac',
                 '-nolisten', 'tcp', '-dpi', '96']
     xvfb_proc = subprocess.Popen(xvfb_cmd, stdout=subprocess.PIPE,
                                  stderr=subprocess.STDOUT)