Change DownloadProcessHandle to be more of an encapsulated class.

chrome/browser/download/download_request_handle.cc

+// Copyright (c) 2011 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/download/download_request_handle.h"
+
+#include "base/stringprintf.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/tab_contents/tab_util.h"
+#include "content/browser/browser_thread.h"
+#include "content/browser/renderer_host/resource_dispatcher_host.h"
+#include "content/browser/tab_contents/tab_contents.h"
+
+// IO Thread indirections to resource dispatcher host.
+// Provided as targets for PostTask from within this object
+// only.
+static void ResourceDispatcherHostPauseRequest(
+    ResourceDispatcherHost* rdh,
+    int process_unique_id,
+    int request_id,
+    bool pause) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  rdh->PauseRequest(process_unique_id, request_id, pause);
+}
+
+static void ResourceDispatcherHostCancelRequest(
+    ResourceDispatcherHost* rdh,
+    int process_unique_id,
+    int request_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  rdh->CancelRequest(process_unique_id, request_id, false);
+}
+
+DownloadRequestHandle::DownloadRequestHandle()
+    : rdh_(NULL),
+      child_id_(-1),
+      render_view_id_(-1),
+      request_id_(-1) {
+}
+
+DownloadRequestHandle::DownloadRequestHandle(ResourceDispatcherHost* rdh,
+                                             int child_id,
+                                             int render_view_id,
+                                             int request_id)
+    : rdh_(rdh),
+      child_id_(child_id),
+      render_view_id_(render_view_id),
+      request_id_(request_id) {
+  // ResourceDispatcherHost should not be null for non-default instances
+  // of DownloadRequestHandle.
+  DCHECK(rdh);
+}
+
+TabContents* DownloadRequestHandle::GetTabContents() const{
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  return tab_util::GetTabContentsByID(child_id_, render_view_id_);
+}
+
+DownloadManager* DownloadRequestHandle::GetDownloadManager() const {
+  TabContents* contents = GetTabContents();
+  if (!contents)
+    return NULL;
+
+  Profile* profile = contents->profile();
+  if (!profile)
+    return NULL;
+
+  return profile->GetDownloadManager();
+}
+
+void DownloadRequestHandle::PauseRequest() {
+  // The post is safe because ResourceDispatcherHost is guaranteed
+  // to outlive the IO thread.
+  if (rdh_) {
+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE,
+        NewRunnableFunction(&ResourceDispatcherHostPauseRequest,
+                            rdh_, child_id_, request_id_, true));
+  }
+}
+
+void DownloadRequestHandle::ResumeRequest() {
+  // The post is safe because ResourceDispatcherHost is guaranteed
+  // to outlive the IO thread.
+  if (rdh_) {
+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE,
+        NewRunnableFunction(&ResourceDispatcherHostPauseRequest,
+                            rdh_, child_id_, request_id_, false));
+  }
+}
+
+void DownloadRequestHandle::CancelRequest() {
+  // The post is safe because ResourceDispatcherHost is guaranteed
+  // to outlive the IO thread.
+  if (rdh_) {
+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE,
+        NewRunnableFunction(&ResourceDispatcherHostCancelRequest,
+                            rdh_, child_id_, request_id_));
+  }
+}
+
+std::string DownloadRequestHandle::DebugString() const {
+  return base::StringPrintf("{"
+                            " child_id = %d"
+                            " render_view_id = %d"
+                            " request_id = %d"
+                            "}",
+                            child_id_,
+                            render_view_id_,
+                            request_id_);
+}