Fix clang warnings about struct vs. class.

Change-Id: I9f26cd01ac3153efa6d77a4133686842e2d63203
diff --git a/include/gui/ISurfaceComposer.h b/include/gui/ISurfaceComposer.h
index 5c3c99c..ffc44c7 100644
--- a/include/gui/ISurfaceComposer.h
+++ b/include/gui/ISurfaceComposer.h
@@ -35,7 +35,7 @@
 
 class ComposerState;
 class DisplayState;
-class DisplayInfo;
+struct DisplayInfo;
 class IDisplayEventConnection;
 class IMemoryHeap;
 
diff --git a/services/surfaceflinger/DisplayDevice.h b/services/surfaceflinger/DisplayDevice.h
index 01a9d2e..46292a4 100644
--- a/services/surfaceflinger/DisplayDevice.h
+++ b/services/surfaceflinger/DisplayDevice.h
@@ -37,7 +37,7 @@
 
 namespace android {
 
-class DisplayInfo;
+struct DisplayInfo;
 class DisplaySurface;
 class IGraphicBufferProducer;
 class Layer;
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.h b/services/surfaceflinger/DisplayHardware/HWComposer.h
index 9f96113..30df461 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.h
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.h
@@ -191,7 +191,7 @@
      * This behaves more or less like a forward iterator.
      */
     class LayerListIterator {
-        friend struct HWComposer;
+        friend class HWComposer;
         HWCLayer* const mLayerList;
         size_t mIndex;