Add chrome://vr-shell-ui internal page

chrome/browser/ui/webui/vr_shell/vr_shell_ui_ui.cc

+// Copyright 2016 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/webui/vr_shell/vr_shell_ui_ui.h"
+
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/webui/vr_shell/vr_shell_ui_message_handler.h"
+#include "chrome/common/url_constants.h"
+#include "content/public/browser/web_ui.h"
+#if !defined(ENABLE_VR_SHELL_UI_DEV)

[xiyuan, 2016/09/15 22:58:47]

nit: insert an empty line before to make it easier to see

[bshe, 2016/09/16 18:27:53]

Done.

+#include "chrome/grit/browser_resources.h"
+#include "content/public/browser/web_ui_data_source.h"
+#else
+#include <map>
+#include "base/macros.h"
+#include "base/memory/ref_counted_memory.h"
+#include "base/strings/string_util.h"
+#include "content/public/browser/url_data_source.h"
+#include "net/url_request/url_fetcher.h"
+#include "net/url_request/url_fetcher_delegate.h"
+#include "net/url_request/url_request_context_getter.h"
+#endif
+
+namespace {
+
+#if defined(ENABLE_VR_SHELL_UI_DEV)
+std::string PathWithoutParams(const std::string& path) {
+  return GURL(std::string("chrome://vr-shell-ui/") + path).path().substr(1);
+}
+
+const char kRemoteBase[] = "http://localhost:8080/";
+const char kRemoteBaseAlt[] = "https://jcarpenter.github.io/hoverboard-ui/";
+const char kRemoteDefaultPath[] = "vr_shell_ui.html";
+const char kHttpNotFound[] = "HTTP/1.1 404 Not Found\n\n";
+
+// RemoteDataSource ---------------------------------------------------------
+
+std::string GetMimeTypeForPath(const std::string& path) {
+  std::string filename = PathWithoutParams(path);
+  if (base::EndsWith(filename, ".html", base::CompareCase::INSENSITIVE_ASCII)) {
+    return "text/html";
+  } else if (base::EndsWith(filename, ".css",
+                            base::CompareCase::INSENSITIVE_ASCII)) {
+    return "text/css";
+  } else if (base::EndsWith(filename, ".js",
+                            base::CompareCase::INSENSITIVE_ASCII)) {
+    return "application/javascript";
+  } else if (base::EndsWith(filename, ".png",
+                            base::CompareCase::INSENSITIVE_ASCII)) {
+    return "image/png";
+  } else if (base::EndsWith(filename, ".gif",
+                            base::CompareCase::INSENSITIVE_ASCII)) {
+    return "image/gif";
+  } else if (base::EndsWith(filename, ".svg",
+                            base::CompareCase::INSENSITIVE_ASCII)) {
+    return "image/svg+xml";
+  } else if (base::EndsWith(filename, ".manifest",
+                            base::CompareCase::INSENSITIVE_ASCII)) {
+    return "text/cache-manifest";
+  }
+  return "text/html";
+}
+
+class RemoteDataSource : public content::URLDataSource,
+                         public net::URLFetcherDelegate {
+ public:
+  using GotDataCallback = content::URLDataSource::GotDataCallback;
+
+  explicit RemoteDataSource(net::URLRequestContextGetter* request_context);
+
+  // content::URLDataSource implementation.
+  std::string GetSource() const override;
+  void StartDataRequest(const std::string& path,
+                        int render_process_id,
+                        int render_frame_id,
+                        const GotDataCallback& callback) override;
+
+ private:
+  // content::URLDataSource overrides.
+  std::string GetMimeType(const std::string& path) const override;
+  bool ShouldAddContentSecurityPolicy() const override;
+  bool ShouldDenyXFrameOptions() const override;
+  bool ShouldServeMimeTypeAsContentTypeHeader() const override;
+
+  // net::URLFetcherDelegate overrides.
+  void OnURLFetchComplete(const net::URLFetcher* source) override;
+
+  ~RemoteDataSource() override;
+
+  scoped_refptr<net::URLRequestContextGetter> request_context_;
+
+  using PendingRequestsMap = std::map<const net::URLFetcher*, GotDataCallback>;
+  PendingRequestsMap pending_;
+  bool localhost_failed_;
+
+  DISALLOW_COPY_AND_ASSIGN(RemoteDataSource);
+};
+
+RemoteDataSource::RemoteDataSource(
+    net::URLRequestContextGetter* request_context)
+    : request_context_(request_context), localhost_failed_(false) {}
+
+RemoteDataSource::~RemoteDataSource() {
+  for (const auto& pair : pending_) {
+    delete pair.first;
+    pair.second.Run(
+        new base::RefCountedStaticMemory(kHttpNotFound, strlen(kHttpNotFound)));
+  }
+}
+
+std::string RemoteDataSource::GetSource() const {
+  return chrome::kChromeUIVrShellUIHost;
+}
+
+void RemoteDataSource::StartDataRequest(
+    const std::string& path,
+    int render_process_id,
+    int render_frame_id,
+    const content::URLDataSource::GotDataCallback& callback) {
+  GURL url = GURL((localhost_failed_ ? kRemoteBaseAlt : kRemoteBase) +
+                  (path.empty() ? std::string(kRemoteDefaultPath) : path));
+  if (!url.is_valid()) {
+    callback.Run(
+        new base::RefCountedStaticMemory(kHttpNotFound, strlen(kHttpNotFound)));
+    return;
+  }
+  net::URLFetcher* fetcher =
+      net::URLFetcher::Create(url, net::URLFetcher::GET, this).release();
+  pending_[fetcher] = callback;
+  fetcher->SetRequestContext(request_context_.get());
+  fetcher->Start();
+}
+
+std::string RemoteDataSource::GetMimeType(const std::string& path) const {
+  return GetMimeTypeForPath(path);
+}
+
+bool RemoteDataSource::ShouldAddContentSecurityPolicy() const {
+  return false;
+}
+
+bool RemoteDataSource::ShouldDenyXFrameOptions() const {
+  return false;
+}
+
+bool RemoteDataSource::ShouldServeMimeTypeAsContentTypeHeader() const {
+  return true;
+}
+
+void RemoteDataSource::OnURLFetchComplete(const net::URLFetcher* source) {
+  DCHECK(source);
+  PendingRequestsMap::iterator it = pending_.find(source);
+  DCHECK(it != pending_.end());
+  std::string response;
+  source->GetResponseAsString(&response);
+
+  delete source;
+  if (response.empty() && !localhost_failed_) {
+    localhost_failed_ = true;
+    content::URLDataSource::GotDataCallback callback = it->second;
+    pending_.erase(it);
+    StartDataRequest("", 0, 0, callback);

[xiyuan, 2016/09/15 22:58:47]

nit: Don't we lose path info with "" ?

[mthiesse, 2016/09/16 15:04:07]

No, an empty string is what URL fetching passes to request the default resource.
If we failed to find the default resource on localhost, we try to find the
default resource on our UI designer's externally hosted site (This is so that we
can debug with localhost, but also have a fallback for when localhost is
disconnected). Also note that this is all temporary code for rapidly prototyping
our UI, the only source we'll launch with are the resource path files.

[mthiesse, 2016/09/16 15:07:24]

Actually, we should be checking here that the path is in fact empty. If the path
is not empty and we've failed to find a file then that's a bug and we should
probably exit (fail a DCHECK).

[bshe, 2016/09/16 18:27:53]

It is easy to make mistakes(such as use a resource before adding it) when
developing.
I don't think using DCHECK is a good idea. We can probably fail silently in that
case and
hopefully devtool could give us error information about the failed request.
I added comment to make this easier to read.

+  } else {
+    it->second.Run(base::RefCountedString::TakeString(&response));
+    pending_.erase(it);
+  }
+}
+#else
+content::WebUIDataSource* CreateVrShellUIHTMLSource() {
+  content::WebUIDataSource* source =
+      content::WebUIDataSource::Create(chrome::kChromeUIVrShellUIHost);
+  source->AddResourcePath("vr_shell_ui.js", IDR_VR_SHELL_UI_JS);
+  source->AddResourcePath("vr_shell_ui.css", IDR_VR_SHELL_UI_CSS);
+  source->SetDefaultResource(IDR_VR_SHELL_UI_HTML);
+  source->DisableI18nAndUseGzipForAllPaths();
+  return source;
+}
+#endif
+
+}  // namespace
+
+VrShellUIUI::VrShellUIUI(content::WebUI* web_ui) : WebUIController(web_ui) {
+  Profile* profile = Profile::FromWebUI(web_ui);
+#if !defined(ENABLE_VR_SHELL_UI_DEV)
+  content::WebUIDataSource::Add(profile, CreateVrShellUIHTMLSource());
+#else
+  RemoteDataSource* source = new RemoteDataSource(profile->GetRequestContext());

[xiyuan, 2016/09/15 22:58:47]

nit: Get rid of |source| and fold into the next line.

[bshe, 2016/09/16 18:27:53]

Done.

+  content::URLDataSource::Add(profile, source);
+#endif
+  web_ui->AddMessageHandler(new VrShellUIMessageHandler);
+}
+
+VrShellUIUI::~VrShellUIUI() {}