Revert "Add full support for line continuation in the preprocessor"

Warning in the Linux/Mac builders:

In file included from ../../third_party/angle/src/tests/preprocessor_tests/input_test.cpp:7:
In file included from ../../third_party/angle/src/tests/preprocessor_tests/PreprocessorTest.h:7:
../../testing/gtest/include/gtest/gtest.h:1392:16: error: comparison of integers of different signs: 'const int' and 'const unsigned long' [-Werror,-Wsign-compare]
  if (expected == actual) {
      ~~~~~~~~ ^  ~~~~~~
../../testing/gtest/include/gtest/gtest.h:1422:12: note: in instantiation of function template specialization 'testing::internal::CmpHelperEQ<int, unsigned long>' requested here
    return CmpHelperEQ(expected_expression, actual_expression, expected,
           ^
../../third_party/angle/src/tests/preprocessor_tests/input_test.cpp:171:5: note: in instantiation of function template specialization 'testing::internal::EqHelper<false>::Compare<int, unsigned long>' requested here
    EXPECT_EQ(3, input.read(buf, maxSize, &lineNo));
    ^

BUG=angleproject:1125

This reverts commit c1157d1963170c7411eb6c32e2b2fbce02c5a170.

Change-Id: Ic6fa286d190b006cccc5154d86e21ecc03175763
Reviewed-on: https://chromium-review.googlesource.com/294080
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/compiler/preprocessor/Input.cpp b/src/compiler/preprocessor/Input.cpp
index 5541d46..f9910a6 100644
--- a/src/compiler/preprocessor/Input.cpp
+++ b/src/compiler/preprocessor/Input.cpp
@@ -29,75 +29,13 @@
     }
 }
 
-const char *Input::skipChar()
-{
-    // This function should only be called when there is a character to skip.
-    assert(mReadLoc.cIndex < mLength[mReadLoc.sIndex]);
-    ++mReadLoc.cIndex;
-    if (mReadLoc.cIndex == mLength[mReadLoc.sIndex])
-    {
-        ++mReadLoc.sIndex;
-        mReadLoc.cIndex = 0;
-    }
-    if (mReadLoc.sIndex >= mCount)
-    {
-        return nullptr;
-    }
-    return mString[mReadLoc.sIndex] + mReadLoc.cIndex;
-}
-
-size_t Input::read(char *buf, size_t maxSize, int *lineNo)
+size_t Input::read(char *buf, size_t maxSize)
 {
     size_t nRead = 0;
-    // The previous call to read might have stopped copying the string when encountering a line
-    // continuation. Check for this possibility first.
-    if (mReadLoc.sIndex < mCount && maxSize > 0)
-    {
-        const char *c = mString[mReadLoc.sIndex] + mReadLoc.cIndex;
-        if ((*c) == '\\')
-        {
-            c = skipChar();
-            if (c != nullptr && (*c) == '\n')
-            {
-                // Line continuation of backslash + newline.
-                skipChar();
-                ++(*lineNo);
-            }
-            else if (c != nullptr && (*c) == '\r')
-            {
-                // Line continuation. Could be backslash + '\r\n' or just backslash + '\r'.
-                c = skipChar();
-                if (c != nullptr && (*c) == '\n')
-                {
-                    skipChar();
-                }
-                ++(*lineNo);
-            }
-            else
-            {
-                // Not line continuation, so write the skipped backslash to buf.
-                *buf = '\\';
-                ++nRead;
-            }
-        }
-    }
-
-    size_t maxRead = maxSize;
-    while ((nRead < maxRead) && (mReadLoc.sIndex < mCount))
+    while ((nRead < maxSize) && (mReadLoc.sIndex < mCount))
     {
         size_t size = mLength[mReadLoc.sIndex] - mReadLoc.cIndex;
         size = std::min(size, maxSize);
-        for (size_t i = 0; i < size; ++i)
-        {
-            // Stop if a possible line continuation is encountered.
-            // It will be processed on the next call on input, which skips it
-            // and increments line number if necessary.
-            if (*(mString[mReadLoc.sIndex] + mReadLoc.cIndex + i) == '\\')
-            {
-                size = i;
-                maxRead = nRead + size;  // Stop reading right before the backslash.
-            }
-        }
         std::memcpy(buf + nRead, mString[mReadLoc.sIndex] + mReadLoc.cIndex, size);
         nRead += size;
         mReadLoc.cIndex += size;