Let ViEEncoder handle resolution changes.

webrtc/test/frame_generator.cc

Index: webrtc/test/frame_generator.cc
diff --git a/webrtc/test/frame_generator.cc b/webrtc/test/frame_generator.cc
index 27935e4b26be0a1575547012e6955e3c1d52fe11..327327343db560ce95fc7f468a3e3fdfe81ef62a 100644
--- a/webrtc/test/frame_generator.cc
+++ b/webrtc/test/frame_generator.cc
@@ -26,8 +26,14 @@ namespace {
 
 class ChromaGenerator : public FrameGenerator {
  public:
-  ChromaGenerator(size_t width, size_t height)
-      : angle_(0.0), width_(width), height_(height) {
+  ChromaGenerator(size_t width, size_t height) : angle_(0.0) {
+    ChangeResolution(width, height);
+  }
+
+  void ChangeResolution(size_t width, size_t height) override {
+    rtc::CritScope lock(&crit_);
+    width_ = width;
+    height_ = height;
     RTC_CHECK(width_ > 0);
     RTC_CHECK(height_ > 0);
     half_width_ = (width_ + 1) / 2;
@@ -36,6 +42,7 @@ class ChromaGenerator : public FrameGenerator {
   }
 
   VideoFrame* NextFrame() override {
+    rtc::CritScope lock(&crit_);
     angle_ += 30.0;
     uint8_t u = fabs(sin(angle_)) * 0xFF;
     uint8_t v = fabs(cos(angle_)) * 0xFF;
@@ -55,6 +62,7 @@ class ChromaGenerator : public FrameGenerator {
   }
 
  private:
+  rtc::CriticalSection crit_;
   double angle_;
   size_t width_;
   size_t height_;