get rid of PixelFormatInfo and simplify things

Change-Id: I025a362cc12d5b9b794fac14be500e25aab65396
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 7f2ce2b..1a25abe 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -176,14 +176,6 @@
 status_t Layer::setBuffers( uint32_t w, uint32_t h,
                             PixelFormat format, uint32_t flags)
 {
-    // this surfaces pixel format
-    PixelFormatInfo info;
-    status_t err = getPixelFormatInfo(format, &info);
-    if (err) {
-        ALOGE("unsupported pixelformat %d", format);
-        return err;
-    }
-
     uint32_t const maxSurfaceDims = min(
             mFlinger->getMaxTextureSize(), mFlinger->getMaxViewportDims());
 
@@ -583,15 +575,19 @@
 // hardware.h, instead of using hard-coded values here.
 #define HARDWARE_IS_DEVICE_FORMAT(f) ((f) >= 0x100 && (f) <= 0x1FF)
 
-bool Layer::getOpacityForFormat(uint32_t format)
-{
+bool Layer::getOpacityForFormat(uint32_t format) {
     if (HARDWARE_IS_DEVICE_FORMAT(format)) {
         return true;
     }
-    PixelFormatInfo info;
-    status_t err = getPixelFormatInfo(PixelFormat(format), &info);
-    // in case of error (unknown format), we assume no blending
-    return (err || info.h_alpha <= info.l_alpha);
+    switch (format) {
+        case HAL_PIXEL_FORMAT_RGBA_8888:
+        case HAL_PIXEL_FORMAT_BGRA_8888:
+        case HAL_PIXEL_FORMAT_RGBA_5551:
+        case HAL_PIXEL_FORMAT_RGBA_4444:
+            return true;
+    }
+    // in all other case, we have no blending (also for unknown formats)
+    return false;
 }
 
 // ----------------------------------------------------------------------------