AAPT2: Fix JavaDoc first sentence extraction.

The old algorithm for detecting the first sentence of a JavaDoc comment
looked for the first occurence of '.'. This does not work when code or a
{@link android.R.styleable} link is encountered in the first sentence.

Switch to checking for whitespace characters after the '.' character.

Bug: 62900335
Test: make aapt2_tests
Change-Id: I8238f6a6304c9c2f92e2e576ca8962a59c2b20ea
diff --git a/tools/aapt2/java/AnnotationProcessor_test.cpp b/tools/aapt2/java/AnnotationProcessor_test.cpp
index 3e43c42..9ccac88 100644
--- a/tools/aapt2/java/AnnotationProcessor_test.cpp
+++ b/tools/aapt2/java/AnnotationProcessor_test.cpp
@@ -18,6 +18,10 @@
 
 #include "test/Test.h"
 
+using ::testing::Eq;
+using ::testing::HasSubstr;
+using ::testing::Not;
+
 namespace aapt {
 
 TEST(AnnotationProcessorTest, EmitsDeprecated) {
@@ -33,7 +37,7 @@
   processor.WriteToStream(&result, "");
   std::string annotations = result.str();
 
-  EXPECT_NE(std::string::npos, annotations.find("@Deprecated"));
+  EXPECT_THAT(annotations, HasSubstr("@Deprecated"));
 }
 
 TEST(AnnotationProcessorTest, EmitsSystemApiAnnotationAndRemovesFromComment) {
@@ -44,10 +48,20 @@
   processor.WriteToStream(&result, "");
   std::string annotations = result.str();
 
-  EXPECT_NE(std::string::npos,
-            annotations.find("@android.annotation.SystemApi"));
-  EXPECT_EQ(std::string::npos, annotations.find("@SystemApi"));
-  EXPECT_NE(std::string::npos, annotations.find("This is a system API"));
+  EXPECT_THAT(annotations, HasSubstr("@android.annotation.SystemApi"));
+  EXPECT_THAT(annotations, Not(HasSubstr("@SystemApi")));
+  EXPECT_THAT(annotations, HasSubstr("This is a system API"));
+}
+
+TEST(AnnotationProcessor, ExtractsFirstSentence) {
+  EXPECT_THAT(AnnotationProcessor::ExtractFirstSentence("This is the only sentence"),
+              Eq("This is the only sentence"));
+  EXPECT_THAT(AnnotationProcessor::ExtractFirstSentence(
+                  "This is the\n  first sentence.  This is the rest of the paragraph."),
+              Eq("This is the\n  first sentence."));
+  EXPECT_THAT(AnnotationProcessor::ExtractFirstSentence(
+                  "This is the first sentence with a {@link android.R.styleable.Theme}."),
+              Eq("This is the first sentence with a {@link android.R.styleable.Theme}."));
 }
 
 }  // namespace aapt