drm_hwcomposer: enable code analysis using clang-tidy

Drm hwcomposer project has some code-style inconsistencies.
This is the initial step to unify code-style of the code.

Clang-tidy is a great tool which can not only suggest correct styling,
but also allow predicting the errors in the code and suggest correct
coding approaches to avoid potential weaknesses.

CI was tuned to check clang-tidy recommendation for some part of the
code which is ready ATM (can be built outside AOSP tree).
For this part a limited set of clang-tidy checks has applied (coarse check).
Header files aren't checked at all.

Starting from now new code files must be included into the list that is
checked by almost all clang-tidy checks (fine checklist). New header files
should be also included into this list.
See '.gitlab-ci-clang-tidy-fine.sh'.

Signed-off-by: Roman Stratiienko <r.stratiienko@gmail.com>
diff --git a/bufferinfo/legacy/BufferInfoLibdrm.cpp b/bufferinfo/legacy/BufferInfoLibdrm.cpp
index c794810..1634f8a 100644
--- a/bufferinfo/legacy/BufferInfoLibdrm.cpp
+++ b/bufferinfo/legacy/BufferInfoLibdrm.cpp
@@ -30,11 +30,11 @@
 LEGACY_BUFFER_INFO_GETTER(BufferInfoLibdrm);
 
 enum chroma_order {
-  YCbCr,
-  YCrCb,
+  kYCbCr,
+  kYCrCb,
 };
 
-struct droid_yuv_format {
+struct DroidYuvFormat {
   /* Lookup keys */
   int native;                     /* HAL_PIXEL_FORMAT_ */
   enum chroma_order chroma_order; /* chroma order is {Cb, Cr} or {Cr, Cb} */
@@ -46,37 +46,37 @@
 
 /* The following table is used to look up a DRI image FourCC based
  * on native format and information contained in android_ycbcr struct. */
-static const struct droid_yuv_format droid_yuv_formats[] = {
+static const struct DroidYuvFormat kDroidYuvFormats[] = {
     /* Native format, YCrCb, Chroma step, DRI image FourCC */
-    {HAL_PIXEL_FORMAT_YCbCr_420_888, YCbCr, 2, DRM_FORMAT_NV12},
-    {HAL_PIXEL_FORMAT_YCbCr_420_888, YCbCr, 1, DRM_FORMAT_YUV420},
-    {HAL_PIXEL_FORMAT_YCbCr_420_888, YCrCb, 1, DRM_FORMAT_YVU420},
-    {HAL_PIXEL_FORMAT_YV12, YCrCb, 1, DRM_FORMAT_YVU420},
+    {HAL_PIXEL_FORMAT_YCbCr_420_888, kYCbCr, 2, DRM_FORMAT_NV12},
+    {HAL_PIXEL_FORMAT_YCbCr_420_888, kYCbCr, 1, DRM_FORMAT_YUV420},
+    {HAL_PIXEL_FORMAT_YCbCr_420_888, kYCrCb, 1, DRM_FORMAT_YVU420},
+    {HAL_PIXEL_FORMAT_YV12, kYCrCb, 1, DRM_FORMAT_YVU420},
     /* HACK: See droid_create_image_from_prime_fds() and
      * https://issuetracker.google.com/32077885. */
-    {HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, YCbCr, 2, DRM_FORMAT_NV12},
-    {HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, YCbCr, 1, DRM_FORMAT_YUV420},
-    {HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, YCrCb, 1, DRM_FORMAT_YVU420},
-    {HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, YCrCb, 1, DRM_FORMAT_AYUV},
-    {HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, YCrCb, 1, DRM_FORMAT_XYUV8888},
+    {HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, kYCbCr, 2, DRM_FORMAT_NV12},
+    {HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, kYCbCr, 1, DRM_FORMAT_YUV420},
+    {HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, kYCrCb, 1, DRM_FORMAT_YVU420},
+    {HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, kYCrCb, 1, DRM_FORMAT_AYUV},
+    {HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED, kYCrCb, 1, DRM_FORMAT_XYUV8888},
 };
 
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
 
 static int get_fourcc_yuv(int native, enum chroma_order chroma_order,
                           int chroma_step) {
-  for (int i = 0; i < ARRAY_SIZE(droid_yuv_formats); ++i)
-    if (droid_yuv_formats[i].native == native &&
-        droid_yuv_formats[i].chroma_order == chroma_order &&
-        droid_yuv_formats[i].chroma_step == chroma_step)
-      return droid_yuv_formats[i].fourcc;
+  for (auto droid_yuv_format : kDroidYuvFormats)
+    if (droid_yuv_format.native == native &&
+        droid_yuv_format.chroma_order == chroma_order &&
+        droid_yuv_format.chroma_step == chroma_step)
+      return droid_yuv_format.fourcc;
 
   return -1;
 }
 
 static bool is_yuv(int native) {
-  for (int i = 0; i < ARRAY_SIZE(droid_yuv_formats); ++i)
-    if (droid_yuv_formats[i].native == native)
+  for (auto droid_yuv_format : kDroidYuvFormats)
+    if (droid_yuv_format.native == native)
       return true;
 
   return false;
@@ -109,11 +109,11 @@
   bo->offsets[0] = (size_t)ycbcr.y;
   /* We assume here that all the planes are located in one DMA-buf. */
   if ((size_t)ycbcr.cr < (size_t)ycbcr.cb) {
-    chroma_order = YCrCb;
+    chroma_order = kYCrCb;
     bo->offsets[1] = (size_t)ycbcr.cr;
     bo->offsets[2] = (size_t)ycbcr.cb;
   } else {
-    chroma_order = YCbCr;
+    chroma_order = kYCbCr;
     bo->offsets[1] = (size_t)ycbcr.cb;
     bo->offsets[2] = (size_t)ycbcr.cr;
   }
@@ -132,7 +132,7 @@
     ALOGW(
         "unsupported YUV format, native = %x, chroma_order = %s, chroma_step = "
         "%d",
-        bo->hal_format, chroma_order == YCbCr ? "YCbCr" : "YCrCb",
+        bo->hal_format, chroma_order == kYCbCr ? "YCbCr" : "YCrCb",
         (int)ycbcr.chroma_step);
     return false;
   }