Fix crash when user closes window prior to the "Confirm Install" prompt showing

chrome/browser/extensions/extension_install_prompt_show_params.cc

Index: chrome/browser/extensions/extension_install_prompt_show_params.cc
diff --git a/chrome/browser/extensions/extension_install_prompt_show_params.cc b/chrome/browser/extensions/extension_install_prompt_show_params.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3b2a7fea35ffb2b9f678dedb6fce96e621779af1
--- /dev/null
+++ b/chrome/browser/extensions/extension_install_prompt_show_params.cc
@@ -0,0 +1,100 @@
+// Copyright 2014 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/extensions/extension_install_prompt_show_params.h"
+
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/native_window_tracker.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_observer.h"
+
+namespace {
+
+Profile* ProfileForWebContents(content::WebContents* web_contents) {
+  if (!web_contents)
+    return nullptr;
+  return Profile::FromBrowserContext(web_contents->GetBrowserContext());
+}
+
+gfx::NativeWindow NativeWindowForWebContents(content::WebContents* contents) {
+  if (!contents)
+    return nullptr;
+
+  return contents->GetTopLevelNativeWindow();
+}
+
+}  // namespace
+
+class ExtensionInstallPromptShowParams::WebContentsDestructionObserver
+    : public content::WebContentsObserver {
+ public:
+  explicit WebContentsDestructionObserver(
+      ExtensionInstallPromptShowParams* params)
+      : content::WebContentsObserver(params->GetParentWebContents()),
+        params_(params) {
+  }
+
+  virtual ~WebContentsDestructionObserver() {
+  }
+
+  virtual void WebContentsDestroyed() override {
+    params_->WebContentsDestroyed();
+  }
+
+ private:
+  // Not owned.
+  ExtensionInstallPromptShowParams* params_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebContentsDestructionObserver);
+};
+
+ExtensionInstallPromptShowParams::ExtensionInstallPromptShowParams(
+    content::WebContents* contents)
+    : profile_(ProfileForWebContents(contents)),
+      parent_web_contents_(contents),
+      parent_web_contents_destroyed_(false),
+      parent_window_(NativeWindowForWebContents(contents)) {
+  if (contents) {
+    web_contents_destruction_observer_.reset(
+        new WebContentsDestructionObserver(this));
+  }
+  if (parent_window_)
+    native_window_tracker_ = NativeWindowTracker::Create(parent_window_);
+}
+
+ExtensionInstallPromptShowParams::ExtensionInstallPromptShowParams(
+    Profile* profile,
+    gfx::NativeWindow parent_window)
+  : profile_(profile),
+    parent_web_contents_(nullptr),
+    parent_web_contents_destroyed_(false),
+    parent_window_(parent_window) {
+  if (parent_window_)
+    native_window_tracker_ = NativeWindowTracker::Create(parent_window_);
+}
+
+ExtensionInstallPromptShowParams::~ExtensionInstallPromptShowParams() {
+}
+
+content::WebContents* ExtensionInstallPromptShowParams::GetParentWebContents() {
+  return parent_web_contents_;
+}
+
+gfx::NativeWindow ExtensionInstallPromptShowParams::GetParentWindow() {
+  return (native_window_tracker_ &&
+          !native_window_tracker_->WasNativeWindowClosed())
+             ? parent_window_
+             : nullptr;
+}
+
+bool ExtensionInstallPromptShowParams::WasParentDestroyed() {
+  return parent_web_contents_destroyed_ ||
+         (native_window_tracker_ &&
+          native_window_tracker_->WasNativeWindowClosed());
+}
+
+void ExtensionInstallPromptShowParams::WebContentsDestroyed() {
+  parent_web_contents_ = nullptr;
+  parent_web_contents_destroyed_ = true;
+}