Fails glLinkProgram if two glBindAttribLocation conflicts.

gpu/command_buffer/service/program_manager.cc

Index: gpu/command_buffer/service/program_manager.cc
===================================================================
--- gpu/command_buffer/service/program_manager.cc	(revision 124489)
+++ gpu/command_buffer/service/program_manager.cc	(working copy)
@@ -5,6 +5,7 @@
 #include "gpu/command_buffer/service/program_manager.h"
 
 #include <algorithm>
+#include <set>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
@@ -168,6 +169,10 @@
     set_log_info("missing shaders");
     return;
   }
+  if (DetectAttribLocationBindingConflicts()) {
+    set_log_info("glBindAttribLocation() conflicts");
+    return;
+  }
 
   glLinkProgram(service_id());
   GLint success = 0;
@@ -442,6 +447,31 @@
   return true;
 }
 
+bool ProgramManager::ProgramInfo::DetectAttribLocationBindingConflicts() const {
+  std::set<GLint> location_binding_used;
+  for (std::map<std::string, GLint>::const_iterator it =
+           bind_attrib_location_map_.begin();
+       it != bind_attrib_location_map_.end(); ++it) {
+    // Find out if an attribute is declared in this program's shaders.
+    bool active = false;
+    for (int ii = 0; ii < kMaxAttachedShaders; ++ii) {
+      if (!attached_shaders_[ii] || !attached_shaders_[ii]->IsValid())
+        continue;
+      if (attached_shaders_[ii]->GetAttribInfo(it->first)) {
+        active = true;
+        break;
+      }
+    }
+    if (active) {
+      std::pair<std::set<GLint>::iterator, bool> result =
+          location_binding_used.insert(it->second);
+      if (!result.second)
+        return true;
+    }
+  }
+  return false;
+}
+
 static uint32 ComputeOffset(const void* start, const void* position) {
   return static_cast<const uint8*>(position) -
          static_cast<const uint8*>(start);