Add unit test and supporting code to test process overflow case.

chrome/browser/renderer_host/test/render_process_host_browsertest.cc

+// Copyright (c) 2010 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.
+
+#include "chrome/browser/browser.h"
+#include "chrome/browser/profile.h"
+#include "chrome/browser/renderer_host/site_instance.h"
+#include "chrome/browser/tab_contents/tab_contents.h"
+#include "chrome/browser/renderer_host/render_process_host.h"
+#include "chrome/common/url_constants.h"
+#include "chrome/test/in_process_browser_test.h"
+#include "chrome/test/ui_test_utils.h"
+
+class RenderProcessHostTest : public InProcessBrowserTest {
+ public:
+  RenderProcessHostTest() {
+    EnableDOMAutomation();
+  }
+
+  int RenderProcessHostCount() {
+    RenderProcessHost::iterator hosts = RenderProcessHost::AllHostsIterator();
+    int count = 0;
+    while (!hosts.IsAtEnd()) {
+      if (hosts.GetCurrentValue()->HasConnection())
+        count++;
+      hosts.Advance();
+    }
+    return count;
+  }
+};
+
+// When we hit the max number of renderers, verify that the way we do process
+// sharing behaves correctly.  In particular, this test is verifying that even
+// when we hit the max process limit, that renderers of each type will wind up
+// in a process of that type, even if that means creating a new process.
+// TODO(erikkay) crbug.com/43448 - disabled for now until we can get a
+// reasonable implementation in place.
+IN_PROC_BROWSER_TEST_F(RenderProcessHostTest, DISABLED_ProcessOverflow) {
+  // Set max renderers to 1 to force running out of processes.
+  RenderProcessHost::SetMaxRendererProcessCount(1);
+
+  int tab_count = 1;
+  int host_count = 1;
+  TabContents* tab1 = NULL;
+  TabContents* tab2 = NULL;
+  RenderProcessHost* rph1 = NULL;
+  RenderProcessHost* rph2 = NULL;
+  RenderProcessHost* rph3 = NULL;
+
+  // Change the first tab to be the new tab page (TYPE_DOMUI).
+  GURL newtab(chrome::kChromeUINewTabURL);
+  ui_test_utils::NavigateToURL(browser(), newtab);
+  EXPECT_EQ(tab_count, browser()->tab_count());
+  tab1 = browser()->GetTabContentsAt(tab_count - 1);
+  rph1 = tab1->GetRenderProcessHost();
+  EXPECT_EQ(tab1->GetURL(), newtab);
+  EXPECT_EQ(host_count, RenderProcessHostCount());
+
+  // Create a new TYPE_NORMAL tab.  It should be in its own process.
+  GURL page1("data:text/html,hello world1");
+  browser()->ShowSingletonTab(page1);
+  if (browser()->tab_count() == tab_count)
+    ui_test_utils::WaitForNewTab(browser());
+  tab_count++;
+  host_count++;
+  EXPECT_EQ(tab_count, browser()->tab_count());
+  tab1 = browser()->GetTabContentsAt(tab_count - 1);
+  rph2 = tab1->GetRenderProcessHost();
+  EXPECT_EQ(tab1->GetURL(), page1);
+  EXPECT_EQ(host_count, RenderProcessHostCount());
+  EXPECT_NE(rph1, rph2);
+
+  // Create another TYPE_NORMAL tab.  It should share the previous process.
+  GURL page2("data:text/html,hello world2");
+  browser()->ShowSingletonTab(page2);
+  if (browser()->tab_count() == tab_count)
+    ui_test_utils::WaitForNewTab(browser());
+  tab_count++;
+  EXPECT_EQ(tab_count, browser()->tab_count());
+  tab2 = browser()->GetTabContentsAt(tab_count - 1);
+  EXPECT_EQ(tab2->GetURL(), page2);
+  EXPECT_EQ(host_count, RenderProcessHostCount());
+  EXPECT_EQ(tab2->GetRenderProcessHost(), rph2);
+
+  // Create another TYPE_DOMUI tab.  It should share the process with newtab.
+  // Note: intentionally create this tab after the TYPE_NORMAL tabs to exercise
+  // bug 43448 where extension and DOMUI tabs could get combined into normal
+  // renderers.
+  GURL history(chrome::kChromeUIHistoryURL);
+  browser()->ShowSingletonTab(history);
+  if (browser()->tab_count() == tab_count)
+    ui_test_utils::WaitForNewTab(browser());
+  tab_count++;
+  EXPECT_EQ(tab_count, browser()->tab_count());
+  tab2 = browser()->GetTabContentsAt(tab_count - 1);
+  EXPECT_EQ(tab2->GetURL(), history);
+  EXPECT_EQ(host_count, RenderProcessHostCount());
+  EXPECT_EQ(tab2->GetRenderProcessHost(), rph1);
+
+  // Create a TYPE_EXTENSION tab.  It should be in its own process.
+  // (the bookmark manager is implemented as an extension)
+  GURL bookmarks(chrome::kChromeUIBookmarksURL);
+  browser()->ShowSingletonTab(bookmarks);
+  if (browser()->tab_count() == tab_count)
+    ui_test_utils::WaitForNewTab(browser());
+  tab_count++;
+  host_count++;
+  EXPECT_EQ(tab_count, browser()->tab_count());
+  tab1 = browser()->GetTabContentsAt(tab_count - 1);
+  rph3 = tab1->GetRenderProcessHost();
+  EXPECT_EQ(tab1->GetURL(), bookmarks);
+  EXPECT_EQ(host_count, RenderProcessHostCount());
+  EXPECT_NE(rph1, rph3);
+  EXPECT_NE(rph2, rph3);
+}