Pass correct length value in WebGamepads

ppapi/shared_impl/ppb_gamepad_shared.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 "ppapi/shared_impl/ppb_gamepad_shared.h"
 
+#include <algorithm>
+
 #include "base/basictypes.h"
 
 namespace ppapi {
 
 void ConvertWebKitGamepadData(const WebKitGamepads& webkit_data,
                               PP_GamepadsSampleData* output_data) {
-  output_data->length = webkit_data.length;
-  for (unsigned i = 0; i < webkit_data.length; ++i) {
+  size_t length = std::min(WebKitGamepads::kItemsLengthCap,
+                          (const size_t)webkit_data.length);

[bbudge, 2015/05/08 17:31:52]

Use C++ style cast. Also, you could avoid a cast by declaring length to be
uint32_t here.

[arajp, 2015/05/11 10:40:40]

Changed to C++ style cast. Changing length to uint32_t required a type cast at
std::min, else Windows build was complaining with:
warning C4267: 'initializing' : conversion from 'size_t' to 'uint32_t', possible
loss of data
So I had to typecast either at min or at the line below. I left it at the line
below.

[bbudge, 2015/05/11 11:21:29]

Would using 'unsigned' to match WebKitGamepads help? Otherwise, it's not worth
too much fussing;
Nit: indent is off by 1 space.

[arajp, 2015/05/11 11:29:20]

Done.

+  output_data->length = static_cast<uint32_t>(length);
+  for (unsigned i = 0; i < length; ++i) {
     PP_GamepadSampleData& output_pad = output_data->items[i];
     const WebKitGamepad& webkit_pad = webkit_data.items[i];
     output_pad.connected = webkit_pad.connected ? PP_TRUE : PP_FALSE;
     if (webkit_pad.connected) {
       static_assert(sizeof(output_pad.id) == sizeof(webkit_pad.id),
                     "id size does not match");
       memcpy(output_pad.id, webkit_pad.id, sizeof(output_pad.id));
       output_pad.timestamp = static_cast<double>(webkit_pad.timestamp);
       output_pad.axes_length = webkit_pad.axes_length;
       for (unsigned j = 0; j < webkit_pad.axes_length; ++j)
         output_pad.axes[j] = static_cast<float>(webkit_pad.axes[j]);
       output_pad.buttons_length = webkit_pad.buttons_length;
       for (unsigned j = 0; j < webkit_pad.buttons_length; ++j)
         output_pad.buttons[j] = static_cast<float>(webkit_pad.buttons[j].value);
     }
   }
 }
 
 }  // namespace ppapi