Simplify ClassLinker::LoadClass

Starting out by removing the ClassLinker::LoadClass to not take a
DexFile. Then started pulling threads so that ClassLinker::LoadClass
could take a StringPiece instead of const char*. Finally went through
and removed all uses of StringPiece::data() to make sure things are
clean.

Change-Id: I47cfa0e8e0e35a31e0ebbd0f7d6a105be83ebe88
diff --git a/src/class_linker_test.cc b/src/class_linker_test.cc
index bbe6ebc..251b6cb 100644
--- a/src/class_linker_test.cc
+++ b/src/class_linker_test.cc
@@ -50,7 +50,7 @@
   scoped_ptr<ClassLinker> linker(ClassLinker::Create());
   linker->AppendToClassPath(dex.get());
 
-  Class* JavaLangObject = linker->FindClass("Ljava/lang/Object;", NULL, dex.get());
+  Class* JavaLangObject = linker->FindClass("Ljava/lang/Object;", NULL);
   ASSERT_TRUE(JavaLangObject != NULL);
   ASSERT_TRUE(JavaLangObject->GetClass() != NULL);
   ASSERT_EQ(JavaLangObject->GetClass(), JavaLangObject->GetClass()->GetClass());
@@ -72,7 +72,7 @@
   EXPECT_EQ(0U, JavaLangObject->NumInstanceFields());
   EXPECT_EQ(0U, JavaLangObject->NumStaticFields());
 
-  Class* MyClass = linker->FindClass("LMyClass;", NULL, dex.get());
+  Class* MyClass = linker->FindClass("LMyClass;", NULL);
   ASSERT_TRUE(MyClass != NULL);
   ASSERT_TRUE(MyClass->GetClass() != NULL);
   ASSERT_EQ(MyClass->GetClass(), MyClass->GetClass()->GetClass());