CloseWebContentsAt returns void

Upstream changes to `CloseWebContentsAt` have changed it to a void
return function. This means that in case of test code, it is necessary
for checks to compare the number of tabs before, and after the
`CloseWebContentsAt` calls.

Chromium change:
https://chromium.googlesource.com/chromium/src/+/85b180cc6fb9d81a6578d75254f5e3ccb7ea3f31

commit 85b180cc6fb9d81a6578d75254f5e3ccb7ea3f31
Author: Simon Hangl <[email protected]>
Date:   Thu Jun 29 18:54:44 2023 +0000

    Reland "Prevent non-closable tabs from being closed"

    This is a reland of commit 889fff9f35c578e4da34c2a2ae4ef4c7bb49130a

    CQ_INCLUDE_TRYBOTS=luci.chrome.try:chromeos-betty-pi-arc-chrome
    CQ_INCLUDE_TRYBOTS=luci.chrome.try:chromeos-eve-chrome
    CQ_INCLUDE_TRYBOTS=luci.chrome.try:chromeos-kevin-chrome
    CQ_INCLUDE_TRYBOTS=luci.chrome.try:chromeos-octopus-chrome
    CQ_INCLUDE_TRYBOTS=luci.chrome.try:chromeos-reven-chrome

    Original change's description:
    > Prevent non-closable tabs from being closed
    >
    > This CL implements admin configurable non-closable apps.
    > These apps should neither be closable through closing the only web app
    > tab (which this CL implements) nor by closing the window containing the
    > app (future CL). The check is placed in `TabStripModel::CloseTabs` to
    > ensure the tab cannot be closed, as all paths to close a tab go through
    > this method. The close prevention is achieved by filtering all tabs
    > that cannot be closed from the list of tabs to close.
    >
    > DD: go/preventclose
    > Bug: b/278246367

browser/ephemeral_storage/blob_url_browsertest.cc

@@ -190,8 +190,10 @@ class BlobUrlBrowserTestBase : public EphemeralStorageBrowserTest {
 
     // Close the first a.com tab, ensure all blobs created there become obsolete
     // and can't be fetched.
-    ASSERT_TRUE(browser()->tab_strip_model()->CloseWebContentsAt(
-        1, TabCloseTypes::CLOSE_NONE));
+    const int previous_tab_count = browser()->tab_strip_model()->count();
+    browser()->tab_strip_model()->CloseWebContentsAt(1,
+                                                     TabCloseTypes::CLOSE_NONE);
+    EXPECT_EQ(previous_tab_count - 1, browser()->tab_strip_model()->count());
     content::RunAllTasksUntilIdle();
     for (size_t idx = 0; idx < a_com2_registered_blobs.size(); ++idx) {
       auto* rfh = a_com2_registered_blobs[idx].rfh.get();
@@ -267,8 +269,10 @@ class BlobUrlBrowserTestBase : public EphemeralStorageBrowserTest {
 
     // Close the first a.com tab, ensure all blobs created there become obsolete
     // and can't be fetched.
-    ASSERT_TRUE(browser()->tab_strip_model()->CloseWebContentsAt(
-        1, TabCloseTypes::CLOSE_NONE));
+    const int previous_tab_count = browser()->tab_strip_model()->count();
+    browser()->tab_strip_model()->CloseWebContentsAt(1,
+                                                     TabCloseTypes::CLOSE_NONE);
+    EXPECT_EQ(previous_tab_count - 1, browser()->tab_strip_model()->count());
     content::RunAllTasksUntilIdle();
     for (size_t idx = 0; idx < a_com2_registered_blobs.size(); ++idx) {
       auto* rfh = a_com2_registered_blobs[idx].rfh.get();

browser/ephemeral_storage/ephemeral_storage_browsertest.cc

@@ -254,9 +254,11 @@ WebContents* EphemeralStorageBrowserTest::LoadURLInNewTab(GURL url) {
 void EphemeralStorageBrowserTest::CloseWebContents(WebContents* web_contents) {
   int tab_index =
       browser()->tab_strip_model()->GetIndexOfWebContents(web_contents);
-  bool was_closed = browser()->tab_strip_model()->CloseWebContentsAt(
-      tab_index, TabCloseTypes::CLOSE_NONE);
-  EXPECT_TRUE(was_closed);
+
+  const int previous_tab_count = browser()->tab_strip_model()->count();
+  browser()->tab_strip_model()->CloseWebContentsAt(tab_index,
+                                                   TabCloseTypes::CLOSE_NONE);
+  EXPECT_EQ(previous_tab_count - 1, browser()->tab_strip_model()->count());
 }
 
 void EphemeralStorageBrowserTest::SetStorageValueInFrame(
@@ -661,9 +663,11 @@ IN_PROC_BROWSER_TEST_F(EphemeralStorageBrowserTest,
   // an eTLD.
   int tab_index =
       browser()->tab_strip_model()->GetIndexOfWebContents(site_a_tab);
-  bool was_closed = browser()->tab_strip_model()->CloseWebContentsAt(
-      tab_index, TabCloseTypes::CLOSE_NONE);
-  EXPECT_TRUE(was_closed);
+
+  const int previous_tab_count = browser()->tab_strip_model()->count();
+  browser()->tab_strip_model()->CloseWebContentsAt(tab_index,
+                                                   TabCloseTypes::CLOSE_NONE);
+  EXPECT_EQ(previous_tab_count - 1, browser()->tab_strip_model()->count());
   EXPECT_TRUE(WaitForCleanupAfterKeepAlive());
 
   // Navigate the main tab to the same site.
@@ -1142,9 +1146,10 @@ IN_PROC_BROWSER_TEST_F(EphemeralStorageKeepAliveDisabledBrowserTest,
   // an eTLD.
   int tab_index =
       browser()->tab_strip_model()->GetIndexOfWebContents(site_a_tab);
-  bool was_closed = browser()->tab_strip_model()->CloseWebContentsAt(
-      tab_index, TabCloseTypes::CLOSE_NONE);
-  EXPECT_TRUE(was_closed);
+  const int previous_tab_count = browser()->tab_strip_model()->count();
+  browser()->tab_strip_model()->CloseWebContentsAt(tab_index,
+                                                   TabCloseTypes::CLOSE_NONE);
+  EXPECT_EQ(previous_tab_count - 1, browser()->tab_strip_model()->count());
 
   // Navigate the main tab to the same site.
   ASSERT_TRUE(

browser/ephemeral_storage/ephemeral_storage_qa_browsertest.cc

@@ -388,9 +388,11 @@ class EphemeralStorageTest : public InProcessBrowserTest {
                "document.getElementById('continue-test-url-step-6').value")
             .ExtractString();
 
-    ASSERT_TRUE(
-        tabs_->CloseWebContentsAt(tabs_->GetIndexOfWebContents(original_tab_),
-                                  TabCloseTypes::CLOSE_NONE));
+    const int previous_tab_count = browser()->tab_strip_model()->count();
+    tabs_->CloseWebContentsAt(tabs_->GetIndexOfWebContents(original_tab_),
+                              TabCloseTypes::CLOSE_NONE);
+    ASSERT_EQ(previous_tab_count - 1, browser()->tab_strip_model()->count());
+
     EphemeralStorageServiceFactory::GetInstance()
         ->GetForContext(browser()->profile())
         ->FireCleanupTimersForTesting();