Improve GLSL integer support

 - Adds shader types for uint.
 - Adds a cap for integer support.
 - Uses glVertexAttribIPointer for integer attribs.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1669853002

Committed: https://skia.googlesource.com/skia/+/3a2caf8ecf38124f4ad21a0f6c4dabfcfa17911a

Review URL: https://codereview.chromium.org/1669853002
diff --git a/include/gpu/GrCaps.h b/include/gpu/GrCaps.h
index 944fb14..fc68206 100644
--- a/include/gpu/GrCaps.h
+++ b/include/gpu/GrCaps.h
@@ -62,6 +62,7 @@
     bool pathRenderingSupport() const { return fPathRenderingSupport; }
     bool dstReadInShaderSupport() const { return fDstReadInShaderSupport; }
     bool dualSourceBlendingSupport() const { return fDualSourceBlendingSupport; }
+    bool integerSupport() const { return fIntegerSupport; }
 
     /**
     * Get the precision info for a variable of type kFloat_GrSLType, kVec2f_GrSLType, etc in a
@@ -109,6 +110,7 @@
     bool fPathRenderingSupport : 1;
     bool fDstReadInShaderSupport : 1;
     bool fDualSourceBlendingSupport : 1;
+    bool fIntegerSupport : 1;
 
     bool fShaderPrecisionVaries;
     PrecisionInfo fFloatPrecisions[kGrShaderTypeCount][kGrSLPrecisionCount];
diff --git a/include/gpu/GrTypesPriv.h b/include/gpu/GrTypesPriv.h
index bc107b5..4026eb7 100644
--- a/include/gpu/GrTypesPriv.h
+++ b/include/gpu/GrTypesPriv.h
@@ -29,8 +29,9 @@
     kSampler2DRect_GrSLType,
     kBool_GrSLType,
     kInt_GrSLType,
+    kUint_GrSLType,
 
-    kLast_GrSLType = kInt_GrSLType
+    kLast_GrSLType = kUint_GrSLType
 };
 static const int kGrSLTypeCount = kLast_GrSLType + 1;
 
@@ -67,7 +68,7 @@
  */
 static inline int GrSLTypeVectorCount(GrSLType type) {
     SkASSERT(type >= 0 && type < static_cast<GrSLType>(kGrSLTypeCount));
-    static const int kCounts[] = { -1, 1, 2, 3, 4, -1, -1, -1, -1, -1, -1, -1 };
+    static const int kCounts[] = { -1, 1, 2, 3, 4, -1, -1, -1, -1, -1, 1, 1, 1 };
     return kCounts[type];
 
     GR_STATIC_ASSERT(0 == kVoid_GrSLType);
@@ -82,6 +83,7 @@
     GR_STATIC_ASSERT(9 == kSampler2DRect_GrSLType);
     GR_STATIC_ASSERT(10 == kBool_GrSLType);
     GR_STATIC_ASSERT(11 == kInt_GrSLType);
+    GR_STATIC_ASSERT(12 == kUint_GrSLType);
     GR_STATIC_ASSERT(SK_ARRAY_COUNT(kCounts) == kGrSLTypeCount);
 }
 
@@ -114,13 +116,14 @@
     GR_STATIC_ASSERT(9 == kSampler2DRect_GrSLType);
     GR_STATIC_ASSERT(10 == kBool_GrSLType);
     GR_STATIC_ASSERT(11 == kInt_GrSLType);
-    GR_STATIC_ASSERT(12 == kGrSLTypeCount);
+    GR_STATIC_ASSERT(12 == kUint_GrSLType);
+    GR_STATIC_ASSERT(13 == kGrSLTypeCount);
 }
 
 /** Is the shading language type integral (including vectors/matrices)? */
 static inline bool GrSLTypeIsIntType(GrSLType type) {
     SkASSERT(type >= 0 && type < static_cast<GrSLType>(kGrSLTypeCount));
-    return type == kInt_GrSLType;
+    return type >= kInt_GrSLType;
 
     GR_STATIC_ASSERT(0 == kVoid_GrSLType);
     GR_STATIC_ASSERT(1 == kFloat_GrSLType);
@@ -134,7 +137,8 @@
     GR_STATIC_ASSERT(9 == kSampler2DRect_GrSLType);
     GR_STATIC_ASSERT(10 == kBool_GrSLType);
     GR_STATIC_ASSERT(11 == kInt_GrSLType);
-    GR_STATIC_ASSERT(12 == kGrSLTypeCount);
+    GR_STATIC_ASSERT(12 == kUint_GrSLType);
+    GR_STATIC_ASSERT(13 == kGrSLTypeCount);
 }
 
 /** Is the shading language type numeric (including vectors/matrices)? */
@@ -158,6 +162,7 @@
         0,                        // kSampler2DRect_GrSLType
         0,                        // kBool_GrSLType
         0,                        // kInt_GrSLType
+        0,                        // kUint_GrSLType
     };
     return kSizes[type];
 
@@ -173,7 +178,8 @@
     GR_STATIC_ASSERT(9 == kSampler2DRect_GrSLType);
     GR_STATIC_ASSERT(10 == kBool_GrSLType);
     GR_STATIC_ASSERT(11 == kInt_GrSLType);
-    GR_STATIC_ASSERT(12 == kGrSLTypeCount);
+    GR_STATIC_ASSERT(12 == kUint_GrSLType);
+    GR_STATIC_ASSERT(13 == kGrSLTypeCount);
 }
 
 static inline bool GrSLTypeIsSamplerType(GrSLType type) {
@@ -202,8 +208,9 @@
     kVec2s_GrVertexAttribType,   // vector of 2 shorts, e.g. texture coordinates
 
     kInt_GrVertexAttribType,
+    kUint_GrVertexAttribType,
     
-    kLast_GrVertexAttribType = kInt_GrVertexAttribType
+    kLast_GrVertexAttribType = kUint_GrVertexAttribType
 };
 static const int kGrVertexAttribTypeCount = kLast_GrVertexAttribType + 1;
 
@@ -211,7 +218,8 @@
  * Returns the vector size of the type.
  */
 static inline int GrVertexAttribTypeVectorCount(GrVertexAttribType type) {
-    static const int kCounts[] = { 1, 2, 3, 4, 1, 4, 2, 1 };
+    SkASSERT(type >= 0 && type < kGrVertexAttribTypeCount);
+    static const int kCounts[] = { 1, 2, 3, 4, 1, 4, 2, 1, 1 };
     return kCounts[type];
 
     GR_STATIC_ASSERT(0 == kFloat_GrVertexAttribType);
@@ -222,6 +230,7 @@
     GR_STATIC_ASSERT(5 == kVec4ub_GrVertexAttribType);
     GR_STATIC_ASSERT(6 == kVec2s_GrVertexAttribType);
     GR_STATIC_ASSERT(7 == kInt_GrVertexAttribType);
+    GR_STATIC_ASSERT(8 == kUint_GrVertexAttribType);
     GR_STATIC_ASSERT(SK_ARRAY_COUNT(kCounts) == kGrVertexAttribTypeCount);
 }
 
@@ -237,7 +246,8 @@
         1*sizeof(char),         // kUByte_GrVertexAttribType
         4*sizeof(char),         // kVec4ub_GrVertexAttribType
         2*sizeof(int16_t),      // kVec2s_GrVertexAttribType
-        sizeof(int32_t)         // kInt_GrVertexAttribType
+        sizeof(int32_t),        // kInt_GrVertexAttribType
+        sizeof(uint32_t)        // kUint_GrVertexAttribType
     };
     return kSizes[type];
 
@@ -249,10 +259,30 @@
     GR_STATIC_ASSERT(5 == kVec4ub_GrVertexAttribType);
     GR_STATIC_ASSERT(6 == kVec2s_GrVertexAttribType);
     GR_STATIC_ASSERT(7 == kInt_GrVertexAttribType);
+    GR_STATIC_ASSERT(8 == kUint_GrVertexAttribType);
     GR_STATIC_ASSERT(SK_ARRAY_COUNT(kSizes) == kGrVertexAttribTypeCount);
 }
 
 /**
+ * Is the attrib type integral?
+ */
+static inline bool GrVertexAttribTypeIsIntType(GrVertexAttribType type) {
+    SkASSERT(type >= 0 && type < static_cast<GrVertexAttribType>(kGrVertexAttribTypeCount));
+    return type >= kInt_GrVertexAttribType;
+
+    GR_STATIC_ASSERT(0 == kFloat_GrVertexAttribType);
+    GR_STATIC_ASSERT(1 == kVec2f_GrVertexAttribType);
+    GR_STATIC_ASSERT(2 == kVec3f_GrVertexAttribType);
+    GR_STATIC_ASSERT(3 == kVec4f_GrVertexAttribType);
+    GR_STATIC_ASSERT(4 == kUByte_GrVertexAttribType);
+    GR_STATIC_ASSERT(5 == kVec4ub_GrVertexAttribType);
+    GR_STATIC_ASSERT(6 == kVec2s_GrVertexAttribType);
+    GR_STATIC_ASSERT(7 == kInt_GrVertexAttribType);
+    GR_STATIC_ASSERT(8 == kUint_GrVertexAttribType);
+    GR_STATIC_ASSERT(9 == kGrVertexAttribTypeCount);
+}
+
+/**
  * converts a GrVertexAttribType to a GrSLType
  */
 static inline GrSLType GrVertexAttribTypeToSLType(GrVertexAttribType type) {
@@ -273,6 +303,8 @@
             return kVec4f_GrSLType;
         case kInt_GrVertexAttribType:
             return kInt_GrSLType;
+        case kUint_GrVertexAttribType:
+            return kUint_GrSLType;
     }
 }
 
diff --git a/include/gpu/gl/GrGLFunctions.h b/include/gpu/gl/GrGLFunctions.h
index 118269b..4d0d654 100644
--- a/include/gpu/gl/GrGLFunctions.h
+++ b/include/gpu/gl/GrGLFunctions.h
@@ -178,6 +178,7 @@
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLVertexAttrib3fvProc)(GrGLuint indx, const GrGLfloat* values);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLVertexAttrib4fvProc)(GrGLuint indx, const GrGLfloat* values);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLVertexAttribDivisorProc)(GrGLuint index, GrGLuint divisor);
+typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLVertexAttribIPointerProc)(GrGLuint indx, GrGLint size, GrGLenum type, GrGLsizei stride, const GrGLvoid* ptr);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLVertexAttribPointerProc)(GrGLuint indx, GrGLint size, GrGLenum type, GrGLboolean normalized, GrGLsizei stride, const GrGLvoid* ptr);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLViewportProc)(GrGLint x, GrGLint y, GrGLsizei width, GrGLsizei height);
 
diff --git a/include/gpu/gl/GrGLInterface.h b/include/gpu/gl/GrGLInterface.h
index 841a513..1a91afb 100644
--- a/include/gpu/gl/GrGLInterface.h
+++ b/include/gpu/gl/GrGLInterface.h
@@ -310,6 +310,7 @@
         GrGLFunction<GrGLVertexAttrib3fvProc> fVertexAttrib3fv;
         GrGLFunction<GrGLVertexAttrib4fvProc> fVertexAttrib4fv;
         GrGLFunction<GrGLVertexAttribDivisorProc> fVertexAttribDivisor;
+        GrGLFunction<GrGLVertexAttribIPointerProc> fVertexAttribIPointer;
         GrGLFunction<GrGLVertexAttribPointerProc> fVertexAttribPointer;
         GrGLFunction<GrGLViewportProc> fViewport;