Add a pdfium_all target.

This can be used to build only the PDFium targets, and skip targets from
projects PDFium depends on, like V8, when one builds "all" targets.

Change-Id: I25b8cd8ac946f6a28adb109d7b175b8a69f9f3d7
Reviewed-on: https://pdfium-review.googlesource.com/3562
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>
diff --git a/BUILD.gn b/BUILD.gn
index 542ae1b..87770fc 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1981,3 +1981,17 @@
     ]
   }
 }
+
+group("pdfium_all") {
+  testonly = true
+  deps = [
+    ":pdfium_embeddertests",
+    ":pdfium_unittests",
+  ]
+  if (pdf_is_standalone) {
+    deps += [
+      ":fuzzers",
+      ":samples",
+    ]
+  }
+}