Add support for passing an arbitrary parameter to an IPC message handler. The motivation is for Web…

content/renderer/browser_plugin/browser_plugin_browsertest.cc

 // Copyright (c) 2012 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 "content/renderer/browser_plugin/browser_plugin_browsertest.h"
 
 #include "base/debug/leak_annotations.h"
 #include "base/files/file_path.h"
 #include "base/memory/singleton.h"
 #include "base/path_service.h"
@@ skipping 251 matching lines @@
     const IPC::Message* create_msg =
         browser_plugin_manager()->sink().GetUniqueMessageMatching(
             BrowserPluginHostMsg_Attach::ID);
     ASSERT_FALSE(create_msg);
 
     const IPC::Message* msg =
         browser_plugin_manager()->sink().GetUniqueMessageMatching(
             BrowserPluginHostMsg_NavigateGuest::ID);
     ASSERT_TRUE(msg);
 
-    int instance_id = 0;
-    std::string src;
-    BrowserPluginHostMsg_NavigateGuest::Read(msg, &instance_id, &src);
+    BrowserPluginHostMsg_NavigateGuest::Param params;
+    BrowserPluginHostMsg_NavigateGuest::Read(msg, &params);
+    std::string src = params.b;
     EXPECT_EQ("bar", src);
     std::string src_value =
         ExecuteScriptAndReturnString(
             "document.getElementById('browserplugin').src");
     EXPECT_EQ("bar", src_value);
   }
 }
 
 TEST_F(BrowserPluginTest, ResizeFlowControl) {
   LoadHTML(GetHTMLForBrowserPluginObject().c_str());
@@ skipping 36 matching lines @@
   for (size_t i = 0; i < browser_plugin_manager()->sink().message_count();
        ++i) {
     const IPC::Message* msg = browser_plugin_manager()->sink().GetMessageAt(i);
     if (msg->type() != BrowserPluginHostMsg_ResizeGuest::ID)
       EXPECT_EQ(msg->type(), BrowserPluginHostMsg_UpdateGeometry::ID);
   }
   const IPC::Message* msg =
       browser_plugin_manager()->sink().GetUniqueMessageMatching(
           BrowserPluginHostMsg_ResizeGuest::ID);
   ASSERT_TRUE(msg);
-  BrowserPluginHostMsg_ResizeGuest_Params params;
-  BrowserPluginHostMsg_ResizeGuest::Read(msg, &instance_id, &params);
+  BrowserPluginHostMsg_ResizeGuest::Param param;
+  BrowserPluginHostMsg_ResizeGuest::Read(msg, &param);
+  instance_id = param.a;
+  BrowserPluginHostMsg_ResizeGuest_Params params = param.b;
   EXPECT_EQ(641, params.view_rect.width());
   EXPECT_EQ(480, params.view_rect.height());
 
   {
     // We send a stale UpdateRect to the BrowserPlugin.
     BrowserPluginMsg_UpdateRect_Params update_rect_params;
     update_rect_params.view_size = gfx::Size(641, 480);
     update_rect_params.scale_factor = 1.0f;
     update_rect_params.is_resize_ack = true;
     BrowserPluginMsg_UpdateRect msg(instance_id, update_rect_params);
@@ skipping 226 matching lines @@
   BrowserPluginMsg_UpdateRect msg(instance_id, update_rect_params);
   browser_plugin->OnMessageReceived(msg);
 
   // Verify that the autosize state has been updated.
   {
     const IPC::Message* auto_size_msg =
         browser_plugin_manager()->sink().GetUniqueMessageMatching(
             BrowserPluginHostMsg_SetAutoSize::ID);
     ASSERT_TRUE(auto_size_msg);
 
-    int instance_id = 0;
-    BrowserPluginHostMsg_AutoSize_Params auto_size_params;
-    BrowserPluginHostMsg_ResizeGuest_Params resize_params;
-    BrowserPluginHostMsg_SetAutoSize::Read(auto_size_msg,
-                                           &instance_id,
-                                           &auto_size_params,
-                                           &resize_params);
+    BrowserPluginHostMsg_SetAutoSize::Param param;
+    BrowserPluginHostMsg_SetAutoSize::Read(auto_size_msg, &param);
+    BrowserPluginHostMsg_AutoSize_Params auto_size_params = param.b;
+    BrowserPluginHostMsg_ResizeGuest_Params resize_params = param.c;
     EXPECT_FALSE(auto_size_params.enable);
     // These value are not populated (as an optimization) if autosize is
     // disabled.
     EXPECT_EQ(0, auto_size_params.min_size.width());
     EXPECT_EQ(0, auto_size_params.min_size.height());
     EXPECT_EQ(0, auto_size_params.max_size.width());
     EXPECT_EQ(0, auto_size_params.max_size.height());
   }
 }
 
 }  // namespace content