[chromecast] Add concrete implementation for CastURLLoaderThrottle.

Bug: b/120907590
Merge-With: eureka-internal/260345
Test: Manual test on device
Change-Id: I5c2063815cbeae78761496871db1bf2e804c82a5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1554901Reviewed-by: Zhongyi Shi <zhongyi@chromium.org>
Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Commit-Queue: Junbo Ke <juke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#649637}

chromecast/common/DEPS

@@ -7,8 +7,9 @@ include_rules = [
   "+extensions/shell/common/api",
   "+extensions/shell/grit",
   "+mojo/public/cpp/bindings",
-  "+services/service_manager/public/cpp",
+  "+net/http",
   "+services/network/public/cpp",
+  "+services/service_manager/public/cpp",
   "+ui/accessibility",
   "+ui/base",
   "+ui/gfx",

chromecast/common/cast_url_loader_throttle.cc

@@ -4,19 +4,51 @@
 
 #include "chromecast/common/cast_url_loader_throttle.h"
 
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/logging.h"
 #include "services/network/public/cpp/resource_request.h"
 #include "services/network/public/cpp/resource_response.h"
 
 namespace chromecast {
 
-CastURLLoaderThrottle::CastURLLoaderThrottle() = default;
+CastURLLoaderThrottle::CastURLLoaderThrottle(
+    Delegate* delegate,
+    const std::string& session_id)
+    : settings_delegate_(delegate),
+      session_id_(session_id),
+      weak_factory_(this) {
+  DCHECK(settings_delegate_);
+  weak_this_ = weak_factory_.GetWeakPtr();
+}
 
 CastURLLoaderThrottle::~CastURLLoaderThrottle() = default;
 
 void CastURLLoaderThrottle::DetachFromCurrentSequence() {}
 
 void CastURLLoaderThrottle::WillStartRequest(
-    network::ResourceRequest* /* request */,
-    bool* defer) {}
+    network::ResourceRequest* request,
+    bool* defer) {
+  int error = settings_delegate_->WillStartResourceRequest(
+      request, session_id_,
+      base::BindOnce(&CastURLLoaderThrottle::ResumeRequest, weak_this_));
+  if (error == net::ERR_IO_PENDING) {
+    deferred_ = true;
+    *defer = true;
+  }
+}
+
+void CastURLLoaderThrottle::ResumeRequest(int error,
+                                          net::HttpRequestHeaders headers) {
+  DCHECK(deferred_);
+  if (error != net::OK) {
+    NOTREACHED() << "Trying to resume a request with unexpected error: "
+                 << error;
+    return;
+  }
+  deferred_ = false;
+  delegate_->UpdateDeferredRequestHeaders(headers);
+  delegate_->Resume();
+}
 
 }  // namespace chromecast

chromecast/common/cast_url_loader_throttle.h

@@ -5,22 +5,50 @@
 #ifndef CHROMECAST_COMMON_CAST_URL_LOADER_THROTTLE_H_
 #define CHROMECAST_COMMON_CAST_URL_LOADER_THROTTLE_H_
 
+#include <string>
+
+#include "base/callback_forward.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "content/public/common/url_loader_throttle.h"
+#include "net/http/http_request_headers.h"
 
 namespace chromecast {
 
 class CastURLLoaderThrottle : public content::URLLoaderThrottle {
  public:
-  CastURLLoaderThrottle();
+  // An interface for CastURLLoaderThrottle to modify the resource request,
+  // possibly also defer the request (by returning net::IO_PENDING) in some
+  // scenarios where blocking operations are needed.
+  class Delegate {
+   public:
+    virtual int WillStartResourceRequest(
+        network::ResourceRequest* request,
+        const std::string& session_id,
+        base::OnceCallback<void(int, net::HttpRequestHeaders)> callback) = 0;
+
+   protected:
+    virtual ~Delegate() = default;
+  };
+
+  CastURLLoaderThrottle(Delegate* delegate, const std::string& session_id);
   ~CastURLLoaderThrottle() override;
 
+ private:
   // content::URLLoaderThrottle implementation:
   void DetachFromCurrentSequence() override;
   void WillStartRequest(network::ResourceRequest* request,
                         bool* defer) override;
 
- private:
+  void ResumeRequest(int error, net::HttpRequestHeaders headers);
+
+  bool deferred_ = false;
+  Delegate* const settings_delegate_;
+  const std::string session_id_;
+
+  base::WeakPtr<CastURLLoaderThrottle> weak_this_;
+  base::WeakPtrFactory<CastURLLoaderThrottle> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(CastURLLoaderThrottle);
 };