mus: Do not host viz by default.

By default, mus will not host viz when chrome is run with --mus. Instead,
it will expect chrome to host viz.

mus will continue to always host viz when chrome is run with --mash.

Bug: 786453
Change-Id: Ifea1a6a953d3e4d20b9d624e156c627a0122a344
Reviewed-on: https://chromium-review.googlesource.com/798776
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521357}

chrome/app/chrome_main.cc

@@ -114,9 +114,6 @@ int ChromeMain(int argc, const char** argv) {
   if (command_line->HasSwitch(switches::kMus)) {
     params.create_discardable_memory = true;
     params.env_mode = aura::Env::Mode::MUS;
-    // TODO(786453): Remove when mus no longer needs to host viz.
-    base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
-        switches::kMus, switches::kMusHostVizValue);
   }
   if (service_manager::ServiceManagerIsRemote() ||
       command_line->HasSwitch(switches::kMash)) {

content/browser/renderer_host/render_widget_host_view_child_frame_browsertest.cc

@@ -23,6 +23,7 @@
 #include "content/test/test_content_browser_client.h"
 #include "net/dns/mock_host_resolver.h"
 #include "net/test/embedded_test_server/embedded_test_server.h"
+#include "ui/base/ui_base_switches_util.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace content {
@@ -155,8 +156,9 @@ IN_PROC_BROWSER_TEST_F(RenderWidgetHostViewChildFrameTest,
 // Tests that while in mus, the child frame receives an updated FrameSinkId
 // representing the frame sink used by the RenderFrameProxy.
 IN_PROC_BROWSER_TEST_F(RenderWidgetHostViewChildFrameTest, ChildFrameSinkId) {
-  // Only in mus do we expect a RenderFrameProxy to provide the FrameSinkId.
-  if (!IsUsingMus())
+  // Only when mus hosts viz do we expect a RenderFrameProxy to provide the
+  // FrameSinkId.
+  if (!switches::IsMusHostingViz())
     return;
 
   GURL main_url(embedded_test_server()->GetURL("/site_per_process_main.html"));

content/test/content_test_launcher.cc

@@ -52,12 +52,6 @@ class ContentBrowserTestSuite : public ContentTestSuiteBase {
  public:
   ContentBrowserTestSuite(int argc, char** argv)
       : ContentTestSuiteBase(argc, argv) {
-#if BUILDFLAG(ENABLE_MUS)
-    // TODO(786453): This should be removed once mus can run without viz.
-    auto* cmd = base::CommandLine::ForCurrentProcess();
-    if (cmd->HasSwitch(switches::kMus))
-      cmd->AppendSwitchASCII(switches::kMus, switches::kMusHostVizValue);
-#endif
   }
   ~ContentBrowserTestSuite() override {}
 

testing/buildbot/filters/mus.content_browsertests.filter

@@ -108,6 +108,7 @@
 -SnapshotBrowserTest.AsyncMultiWindowTest
 -SnapshotBrowserTest.SingleWindowTest
 -SnapshotBrowserTest.SyncMultiWindowTest
+-WebContentsViewAuraTest.ReplaceStateReloadPushState
 -WebRtcCaptureFromElementBrowserTest.CaptureFromCanvas2DHandlesContextLoss
 -WebRtcCaptureFromElementBrowserTest.CaptureFromOpaqueCanvas2DHandlesContextLoss