Allow FakeVideoCaptureDeviceFactory to specify number of supported formats per device.

media/capture/video/fake_video_capture_device_factory.cc

Index: media/capture/video/fake_video_capture_device_factory.cc
diff --git a/media/capture/video/fake_video_capture_device_factory.cc b/media/capture/video/fake_video_capture_device_factory.cc
index 3886f48daea5b1e05fadf6c107e3166ae9255dc8..d599bc79c5c5791f32494efb8e0255c6e68d12d9 100644
--- a/media/capture/video/fake_video_capture_device_factory.cc
+++ b/media/capture/video/fake_video_capture_device_factory.cc
@@ -5,6 +5,7 @@
 #include "media/capture/video/fake_video_capture_device_factory.h"
 
 #include "base/command_line.h"
+#include "base/macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_tokenizer.h"
@@ -36,9 +37,11 @@ static const float kFakeCaptureDefaultFrameRate = 20.0f;
 // Cap the device count command line input to reasonable values.
 static const int kFakeCaptureMinDeviceCount = 1;
 static const int kFakeCaptureMaxDeviceCount = 10;
+static const int kFakeCaptureMinFormatCount = 0;
 
 FakeVideoCaptureDeviceFactory::FakeVideoCaptureDeviceFactory()
     : number_of_devices_(1),
+      number_of_formats_per_device_(5),
       fake_vcd_ownership_(FakeVideoCaptureDevice::BufferOwnership::OWN_BUFFERS),
       frame_rate_(kFakeCaptureDefaultFrameRate) {}
 
@@ -107,9 +110,13 @@ void FakeVideoCaptureDeviceFactory::GetSupportedFormats(
       gfx::Size(96, 96), gfx::Size(320, 240), gfx::Size(640, 480),
       gfx::Size(1280, 720), gfx::Size(1920, 1080)};
   supported_formats->clear();
-  for (const auto& size : supported_sizes) {
-    supported_formats->push_back(VideoCaptureFormat(
-        size, frame_rate_, GetPixelFormat(device_descriptor.device_id)));
+  size_t num_formats =
+      std::min(arraysize(supported_sizes),
+               static_cast<size_t>(number_of_formats_per_device_));
+  for (size_t i = 0; i < num_formats; ++i) {
+    supported_formats->push_back(
+        VideoCaptureFormat(supported_sizes[i], frame_rate_,
+                           GetPixelFormat(device_descriptor.device_id)));
   }
 }
 
@@ -153,6 +160,13 @@ void FakeVideoCaptureDeviceFactory::ParseCommandLine() {
             kFakeCaptureMaxDeviceCount,
             std::max(kFakeCaptureMinDeviceCount, static_cast<int>(count)));
       }
+    } else if (base::EqualsCaseInsensitiveASCII(param.front(),
+                                                "format-count")) {
+      unsigned int count = 0;
+      if (base::StringToUint(param.back(), &count)) {
+        number_of_formats_per_device_ =
+            std::max(kFakeCaptureMinFormatCount, static_cast<int>(count));
+      }

[mcasas, 2017/02/14 17:01:01]

I think adding a new command line flag and member variable
is overkill just for a unittest (media_devices_dispatcher_host_unittest.cc).

Can we do it some other way? E.g. by adding a new
ReturnNoEnumeratedFormatsForTesting() to FakeVCDFactory ?

     }
   }
 }