Introduce BrowserIterator.

An iterator meant to iterate over all the browsers in BrowserListImpls across multiple desktops (i.e. multiple HostDesktopTypes).

As a first step, used it in TabContentsIterator (pretty much bringing back the implementation to the one that was there prior to https://codereview.chromium.org/11316340/ -- except that the iterator is now aware of multiple desktops).

Another CL will follow in which all BrowserList::const_iterator, etc. methods will be replaced by BrowserIterator.

The interface of BrowserIterator is derived from the interface of TabContentsIterator for consistency (which is being slightly tweaked in parallel in https://codereview.chromium.org/12049038/).

BUG=129187

Review URL: https://chromiumcodereview.appspot.com/12038053

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@179695 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 33 insertions, 0 deletions

diff --git a/chrome/browser/ui/browser_iterator.cc b/chrome/browser/ui/browser_iterator.cc
new file mode 100644
index 0000000..73571d5
--- /dev/null
+++ b/chrome/browser/ui/browser_iterator.cc
@@ -0,0 +1,33 @@
+// Copyright (c) 2013 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/ui/browser_iterator.h"
+
+namespace chrome {
+
+BrowserIterator::BrowserIterator()
+    : current_browser_list_(
+          BrowserListImpl::GetInstance(HOST_DESKTOP_TYPE_FIRST)),
+      current_iterator_(current_browser_list_->begin()),
+      next_desktop_type_(
+          static_cast<HostDesktopType>(HOST_DESKTOP_TYPE_FIRST + 1)) {
+  NextBrowserListIfAtEnd();
+}
+
+void BrowserIterator::Next() {
+  ++current_iterator_;
+  NextBrowserListIfAtEnd();
+}
+
+void BrowserIterator::NextBrowserListIfAtEnd() {
+  // Make sure either |current_iterator_| is valid or done().
+  while (current_iterator_ == current_browser_list_->end() &&
+         next_desktop_type_ < HOST_DESKTOP_TYPE_COUNT) {
+    current_browser_list_ = BrowserListImpl::GetInstance(next_desktop_type_);
+    current_iterator_ = current_browser_list_->begin();
+    next_desktop_type_ = static_cast<HostDesktopType>(next_desktop_type_ + 1);
+  }
+}
+
+}  // namespace chrome