Pepper: add Image Capture interfaces.

ppapi/api/private/ppb_camera_capabilities_private.idl

+/* Copyright (c) 2014 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.
+ */
+
+/**
+ * This file defines the PPB_CameraCapabilities_Private interface for
+ * establishing an image capture configuration resource within the browser.
+ */
+
+[generate_thunk]
+
+label Chrome {
+  M39 = 0.1
+};
+
+/**
+ * The <code>PPB_CameraCapabilities_Private</code> interface contains pointers to

[Owen Lin, 2014/08/07 07:45:04]

line too long.

[wuchengli, 2014/08/07 15:33:55]

Done.

+ * several functions for getting the image capture capabilities within the
+ * browser.
+ */
+[version=0.1]
+interface PPB_CameraCapabilities_Private {
+  /**
+   * IsCameraCapabilities() determines if the given resource is a
+   * <code>PPB_CameraCapabilities_Private</code>.
+   *
+   * @param[in] resource A <code>PP_Resource</code> corresponding to an image
+   * capture capabilities resource.
+   *
+   * @return A <code>PP_Bool</code> containing <code>PP_TRUE</code> if the given
+   * resource is an <code>PP_CameraCapabilities_Private</code> resource,
+   * otherwise <code>PP_FALSE</code>.
+   */
+  PP_Bool IsCameraCapabilities(
+      [in] PP_Resource resource);
+
+  /**
+   * GetSupportedPreviewSize() returns the supported preview sizes for the given

[Pawel Osciak, 2014/08/07 06:22:46]

s/Size/Sizes/

[wuchengli, 2014/08/07 15:33:55]

Done.

+   * <code>PPB_CameraCapabilities_Private</code>.
+   *
+   * @param[in] capabilities A <code>PP_Resource</code> corresponding to an
+   * image capture capabilities resource.
+   * @param[out] count The count of preview size array.

[Pawel Osciak, 2014/08/07 06:22:46]

s/count/size/

[wuchengli, 2014/08/07 15:33:54]

Done. I used count because several other ppapi used count. I also prefer size.

+   *
+   * @return An array of <code>PP_Size</code> corresondping to

[Justin Chuang, 2014/08/07 04:27:28]

typo

[wuchengli, 2014/08/07 15:33:54]

Done.

+   * the supported preview sizes in pixels.
+   */
+  [on_failure=NULL]
+  PP_Size[] GetSupportedPreviewSizes(
+      [in] PP_Resource capabilities,
+      [out] int32_t count);

[Justin Chuang, 2014/08/07 04:27:27]

When to free the output PPSize[]?

A similar example is PPP_Flash_BrowserOperations

  void GetSitesWithData([in] str_t plugin_data_path,
                        [out] fstr_t[] sites);
    =>
  void (*GetSitesWithData)(const char* plugin_data_path, char** sites[]);

It requires   
   void (*FreeSiteList)(char* sites[]);
to release the memory.

Another method is to return a PP_Var, which contains an array. 
Don't know which method is better.

[wuchengli, 2014/08/07 15:33:54]

Good point. If the ownership belongs to the caller, we can use
PPB_Memory_Dev.MemFree. I think it's more convenient if the ownership belongs to
this class. The caller will own a PPB_CameraCapabilities_Private object anyway,
which contains the memory of preview sizes and picture sizes. The caller doesn't
need another copy when calling this function. If there is a need, the caller can
allocate a new array and copy out. I added some comments.

+
+  /**
+   * GetSupportedJPEGSize() returns the supported JPEG sizes for the given
+   * <code>PPB_CameraCapabilities_Private</code>.
+   *
+   * @param[in] capabilities A <code>PP_Resource</code> corresponding to an
+   * image capture capabilities resource.
+   * @param[out] count The count of JPEG size array. If the output of this
+   * is 0, the camera has no support for generating JPEG images.
+   *
+   * @return An array of <code>PP_Size</code> corresondping to the supported
+   * JPEG image sizes in pixels.
+   */
+  [on_failure=NULL]
+  PP_Size[] GetSupportedJPEGSizes(

[Owen Lin, 2014/08/07 07:45:04]

In func name, I believe the naming convention suggests using "Jpeg".

http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Function_Names

where it use Url not URL. 

[wuchengli, 2014/08/07 15:33:54]

Pawel suggested JPEG. I just searched the code base. The only function not in
third_party that has JPEG is JpegLibraryVariant. I searched for URL and people
use both URL and Url. I personally prefer Jpeg. Pawel. I'm changing this back to
Jpeg.

+      [in] PP_Resource capabilities,

[Owen Lin, 2014/08/07 07:45:04]

It's kind of strange to return the array and size differently.

FYR: "private/finish_writing_these/ppb_pdf.idl"

[wuchengli, 2014/08/07 15:33:55]

Done. I thought this generated failure when running generator.py.

+      [out] int32_t count);
+};